JP2020074536A - Reference signal in communication network - Google Patents

Abstract

To provide a method in a user apparatus for transmitting a demodulation reference signal in a communication network.SOLUTION: A method includes the steps of: determining multiplexed information on demodulation reference signals; transmitting the demodulation reference signals by using the multiplexed information in time assignment the same as that of the demodulation reference signals of another user apparatus; and transmitting data symbols associated with the demodulation reference signals with individual time assignment of a physical resource and the same physical frequency resource with respect to time assignment of data symbols of the different user apparatus.SELECTED DRAWING: Figure 11

Description

  The present application relates generally to transmitting and receiving reference signals and data in communication networks.

  Packet data latency is one of the performance metrics that vendors, operators, and even end users regularly measure. Latency measurement is performed at all stages of the radio access network system life, eg, when verifying new software releases or system components, when deploying the system, and when the system is operating on a commercial basis.

  Radio resource efficiency can be positively impacted by reduced latency. The lower packet data latency increases the number of transmissions possible within a certain delay bound. Therefore, higher block error rate (BLER) targets may be used for data transmission, freeing radio resources, and possibly improving system capacity.

  Furthermore, resource allocation in Long Term Evolution (LTE) is typically described in terms of resource blocks, where a resource block is 1 slot (0.5 ms) in the time domain and 12 subs in the frequency domain. Corresponds to a carrier. The resource blocks are numbered starting from 0 at one end of the system bandwidth in the frequency domain.

  LTE is a radio access technology based on radio access network control and scheduling. These facts impact latency performance as the transmission of data requires lower layer control signaling round trips.

  The data is created by higher layers and the User Equipment (UE) modem needs to send a Scheduling Request (SR) to the Evolved NodeB (eNB). The eNB processes this SR and responds with a grant so that the uplink data transfer can be initiated.

  FIG. 1 shows an LTE release 8 mapping user data symbols and reference signals in two physical uplink shared channel (PUSCH) subframes 10, labeled first subframe 10a and second subframe 10b. An example is shown. Subframe 10 is in the time / frequency structure. Each row 11 corresponds to a subcarrier of a different frequency (eg divided by 15 kHz) and each column 12 corresponds to a symbol interval at a different time or basic time unit 12. The resource element 13 consists of one subcarrier in one symbol. Each sub-frame 10a, 10b comprises 14 symbols in time (for a normal length cyclic prefix) labeled 0-13. Each of the subframes 10a and 10b is organized by two slots of 7 symbols each and a plurality of subcarriers of frequencies. A resource block (or physical resource block) is defined as one slot in time and 180 kHz (for example, 12 subcarriers) in frequency. A resource block pair or a physical resource block pair may be used to refer to two such resource blocks. References to subframes may alternatively be referred to as resource block pairs or physical resource block pairs. For example, the physical resource block has a limited frequency range (for example, one set of 12 subcarriers). Data for only one UE is sent in physical resource block pairs.

  As defined in 3GPP TS 36.211, in LTE Release 8, the reference signal in the PUSCH subframe is transmitted once per slot and is located in the center of each slot as shown in FIG. The numbers in the resource element grid refer to an exemplary transmission time interval (TTI) in which the transport block is transmitted. Each column indicates the resource element used to transmit the symbol. The number in the lower part of FIG. 1 indicates the index of the uplink symbol in the LTE Release 8 subframe in this example.

  Reference signal “R” 16 is inserted into SC-FDMA symbol number 3 and symbol number 10 in the subframe. In the first subframe 10a, data symbols are transmitted in all symbols except reference symbols.

  The first subframe 10a is transmitted by the first UE and the data symbols 13 are correspondingly labeled with "1". The second subframe 10b is transmitted by the second UE of the cell and the data symbols 13 are correspondingly labeled with "2". The reference signal R16 in the first subframe 10a is transmitted by the first UE, and the reference signal R16 in the second subframe 10b is transmitted by the second UE. The reference signal transmitted in the first subframe 10a may be used for channel estimation of the data symbols 13 of the first subframe 10a and the reference signal transmitted in the second subframe 10b may be It may be used for channel estimation of the data symbols 13 of the two subframes 10b.

  For single carrier formats such as those used in LTE uplink, each signal spans multiple resource elements and is not located in a single resource element. This is in contrast to Orthogonal Frequency Division Multiplexing (OFDM) used in the LTE downlink.

  Wireless access within LTE includes, for example, 3GPP TS 36.211, "Physical Channels and Modulation" technical specifications, 3rd Generation Partnership Project, Specification Group Radio Access Network, Enhanced Universal Terrestrial Radio Access (E-UTRA), V12.5. .0 based on DFT spread OFDM, also referred to as OFDM on the downlink and single carrier frequency division multiple access FDMA (SC-FDMA) on the uplink. The signal transmitted on the uplink is precoded by the DFT, mapped to the allocated frequency intervals, transformed into the time domain, concatenated with the cyclic prefix and finally transmitted over the air. The symbols constructed by DFT, mapping, IFFT, and CP insertion are shown as SC-FDMA symbols. Within LTE Release 8, the TTI is constructed with 14 such SC-FDMA symbols for a regular cyclic prefix, as shown in FIG.

  This DFT spread OFDM as used in the uplink has a significantly lower peak-to-average power ratio (PAPR) compared to OFDM. The low PAPR allows the sender to be equipped with simpler and less energy consuming wireless equipment, which is important for user devices where cost and battery consumption are important issues.

  The reference signal represents an overhead in which user data is not transmitted. Increasing user data transmission is beneficial for increasing data transfer rates. Reducing latency is also advantageous.

  A first aspect of the present disclosure provides a method in a user equipment for transmitting a demodulation reference signal in a communication network. The method includes determining multiplexing information for a demodulation reference signal and transmitting the demodulation reference signal using the multiplexing information in the same time allocation as another user equipment demodulation reference signal. .. The method comprises transmitting the data symbols associated with the demodulation reference signal in a separate time allocation of physical resources and in the same physical frequency resource, relative to the time allocation of the data symbols of the other user equipment described above. Further includes.

  Therefore, the overhead represented by the reference signal is reduced. This is particularly advantageous when the TTI of user data is reduced, for example, to less than one subframe or less than one slot in time.

  A second aspect of the disclosure provides a method at a base station for communicating with user equipment in a communication network. The method includes receiving a first reference signal from a first user equipment and receiving a second reference signal from a second user equipment. The first reference signal and the second reference signal are multiplexed. The method further includes receiving a first data symbol from the first user equipment and receiving a second data symbol from the second user equipment. Data symbols from the first user equipment and the second user equipment are received on separate time allocations of physical resources and on the same physical frequency resource.

  A third aspect of the present disclosure provides a user equipment configured to transmit a demodulation reference signal in a communication network. The user equipment uses the processing circuit configured to determine the multiplexing information for the demodulation reference signal and the demodulation reference signal using the multiplexing information in the same time allocation as the demodulation reference signal of another user equipment. And a wireless circuit configured to transmit. The radio circuit is arranged to transmit the data symbols associated with the demodulation reference signal in a separate time allocation of physical resources and in the same physical frequency resource as compared to the time allocation of the data symbols of the other user equipment described above. Is composed of.

  A fourth aspect of the disclosure provides a base station configured to communicate with user equipment in a communication network. The method includes a wireless circuit configured to receive a first reference signal from a first user equipment and a second reference signal from a second user equipment. The first reference signal and the second reference signal are multiplexed. The radio circuit is configured to receive the first data symbol from the first user equipment and the second data symbol from the second user equipment. The data symbols from the first user equipment and the second user equipment are in separate time allocations of physical resources and in the same physical frequency resource.

  A fifth aspect of the disclosure provides a computer program product configured to, when run on a computer, perform the method as described.

  Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings.

FIG. 3 is a diagram showing a prior art of allocation of reference signals and data to subframes for transmission. FIG. 3 is a diagram illustrating an example of a network according to an example of the present disclosure. FIG. 6 is a diagram illustrating an example of reference signal and data symbol allocation to transmission subframes, according to an aspect of the disclosure. FIG. 6 is a diagram illustrating a further example of allocation of reference signals and data symbols to subframes for transmission according to one aspect of the disclosure. FIG. 6 is a diagram illustrating a further example of allocation of reference signals and data symbols to subframes for transmission according to one aspect of the disclosure. FIG. 6 is a diagram illustrating a further example of allocation of reference signals and data symbols to subframes for transmission according to one aspect of the disclosure. FIG. 6 is a diagram illustrating a further example of allocation of reference signals and data symbols to subframes for transmission according to one aspect of the disclosure. FIG. 6 is a diagram illustrating a further example of allocation of reference signals and data symbols to subframes for transmission according to one aspect of the disclosure. FIG. 3 shows a schematic overview of a base station according to an example of the present disclosure. FIG. 5 shows a schematic overview of user equipment according to an example of the present disclosure. FIG. 7 illustrates an example method in user equipment according to an example of the present disclosure. FIG. 6 illustrates an example method at a base station according to an example of the present disclosure.

  Although the examples of this disclosure relate to multiplexing reference signals from or to several transmitters on the same symbol, user data from or to different transmitters is a separate symbol. Sent. The symbols may be SC-FDMA symbols in the uplink from multiple UEs, for example.

  The amount of overhead in resource allocation is significantly reduced by multiplexing reference signals from (or to) multiple UEs on the same symbol. On the other hand, user data from one UE is not interfered with by other UEs, because each UE has a dedicated symbol (eg, SC-FDMA symbol) for the user data. The single carrier property of the transmission (eg uplink) may be preserved, which has a positive impact on the cost and power consumption of the device.

  FIG. 2 shows an example of a communication network 100, this embodiment relates to the transmission or signaling information of a reference signal, eg a demodulation reference signal (DMRS). In some examples, the reference signal transmission is a multiplex transmission scheme of transmissions from multiple UEs in a cell. Communication network 100 is applicable to one or more radio access technologies such as, for example, LTE, LTE-Advanced, WCDMA, GSM, or any 3GPP or other radio access technology.

  Communication network 100 includes network nodes, such as base station 103 serving cell 101, for example. The base station 103 is capable of communicating on a radio carrier 102 with a radio base station, a NodeB, eg an eNB depending on the technology and terminology used, or a first user equipment 105 present in the cell 101. It may be a base station such as another network unit of The wireless carrier 102 may also be referred to as a carrier, wireless channel, channel, communication link, wireless link, or link. The base stations 103 may be of various classes, eg macro base stations, eg eNodeB, or low power base stations, eg home eNodeB, pico base stations or femto base stations based on transmission power and thus also cell size. It may be Although FIG. 2 shows a base station 103 serving one cell 101, the base station 103 can serve more than one cell 101. Communication network 100 may further include one or more other user equipments, eg, second user equipment 107 and third user equipment 109. In some embodiments, the second user equipment 107 and the second user equipment 109 are in the same cell 101 as the first user equipment 105 and are served by the same base station 103.

  Communication network 100 may be partitioned into cells, such as cell 101, for example. Therefore, the communication network 100 may be referred to as a cellular communication network. A cell is a geographical area where a base station 103 serving cell 101 provides wireless coverage to user equipment 105 residing in cell 101. Cell 101 may be, for example, a microcell that typically covers a limited area, a picocell that typically covers a small area, a femtocell typically designed for use in a home or small business, Alternatively, they may be of different sizes, such as macro cells, which typically provide wider coverage than micro cells.

  User equipment 105 residing in cell 101 and served by base station 103 can then communicate with base station 103 on wireless carrier 102. The data stream is communicated between base station 103 and user equipment 105 over wireless channel 102 in a layered approach. Examples of layers include physical layer, data link layer, network layer, transport layer, session layer and the like.

  User equipment 105 is any suitable communication or computing device having communication capabilities capable of communicating with base station 103 over wireless channel 102, such as, but not limited to, mobile phones, smartphones, personal digital assistants (PDAs). ), Laptops, MP3 players or portable DVD players (or similar media content devices), digital cameras, or even stationary devices such as PCs. The PC may be connected via a mobile station as a terminal station for broadcast / multicast media. The user equipment 105 may be a communication device incorporated in, for example, an electronic photo frame, a heart monitoring device, an intrusion monitoring device or other monitoring device, a weather data monitoring system, a vehicle, an automobile or a transport communication device. User equipment 105 is referred to as a UE in some of the drawings. The base station 103 can serve a set of multiple user equipments 105, 107, 109. A UE may alternatively be referred to as an end device, terminal device, user, or terminal.

  It should be noted that the wireless carrier 102 between the base station 103 and the user equipment 105 may be of any suitable type including either a wired link or a wireless link. The carrier 102 can use any suitable protocol depending on the type and level of layers, as dictated by the Open Systems Interconnection (OSI) model, as will be appreciated by those skilled in the art. ..

  The description below uses the uplink (UL) transmission path of an LTE network as an example, but the example is applicable to downlink (DL) and / or other communication protocols, eg as described above. .. UL is the link from the user equipment to the base station and DL is the link from the base station to the user equipment.

  FIG. 3 shows an example of a subframe 30 of physical transmission resources scheduled for a plurality of UEs. Subframe 30 corresponds to LTE Release 8 as described above, except as otherwise noted. The symbols 13 correspond to user data or reference signals and, in some examples, control data. The term subframe may be used to indicate the time period of a physical resource block pair. Alternatively, the subframe is a subframe time period and a defined frequency range (eg, one or more multiples of 12 subcarriers) or one or more physical resource blocks or physical resource blocks. May be used to indicate a pair.

  The information sent on the air interface is called the payload. A subframe (eg, PUSCH subframe) may carry, in addition to the payload, any control information needed to decode the payload, such as transport format indicators and MIMO parameters. Such control data is multiplexed with the payload before DFT spreading. The payload and control data may both be referred to as user data or data that is different from the reference signal.

  In the example shown in FIG. 3, scheduling for each UE is based on less than one subframe, eg, subframe 30a or 30b. In this case, the UE is scheduled with resources of less than 14 symbols or 1 ms. In this example, the first subframe 30a is designated to two UEs, for example, the first UE 105 and the second UE 107. This is in contrast to conventional scheduling, where a 1 ms subframe is assigned to only one UE. The first allocation 32a comprises 7 symbols in time and the second allocation 32b also comprises 7 symbols in time. In this example, the allocations 32a and 32b correspond to the length of one resource block, but the example is not so limited.

  In some examples, the scheduled resource is on the uplink. For example, resources relate to PUSCH assignments in subframes, physical resource blocks, or physical resource block pairs. The symbols are SC-FDMA symbols. Therefore, PUSCH assignment does not cover all SC-FDMA symbols in a 1 ms subframe. In some aspects the frequency resource allocation is as is known in the art, eg, a resource block has 12 subcarriers. Aspects of the disclosure are also applicable to transmissions on the physical uplink control channel (PUCCH).

  Assignments 32a, 32b are transmission time intervals (TTIs) for different UEs, respectively. The number "1" in the symbol of the first allocation 32a represents a data symbol for the first UE and the number "2" in the symbol of the second allocation 32b represents a data (eg, user data) symbol for the second UE. .. In this example, 6 SC-FDMA symbols of data (eg user data) are included in the same TTI.

  Subframe 30 includes one or more reference signals 36, eg, DM-RSs corresponding to the reference signals described above.

  FIG. 3 shows eight subcarriers (ie, rows) marked to indicate data symbols or reference symbols. The number of rows displayed is merely indicative of the principles of the present disclosure and neither example is limited to 8 subcarriers. For example, 12 subcarriers (rows), or multiples thereof, may be used in either example.

  The reference signal transmitted by the UE is in the uplink direction and is used by the base station (eg eNodeB) to estimate the channel for use in demodulation and decoding of user data, to estimate timing and frequency errors. , And / or estimate the uplink channel quality. The eNodeB may separately use the Sounding Reference Signal (SRS), eg, for uplink frequency selective scheduling or uplink timing estimation as part of the timing alignment procedure.

  In this example, the first UE transmitting data symbols in the first allocation 32a also transmits the reference signal 36 in the first allocation 32a (ie, in symbol 3). In this example, the first UE also transmits additional reference symbols outside the time of its data symbol allocation. In this case, the first UE transmits the reference signal in the second allocation 32b, ie in the symbol 10 of the first subframe 30a. Out-of-time of a data symbol may refer to the time of allocation to a different resource block, subframe, or symbol that is not temporally contiguous with another user's or UE's allocated resources for user data. .. This allows the UE to follow the time variation of the radio channel which is outside the time of this data symbol allocation. In this situation, the reference signal 36 is in the central position of the first allocation 32a and in the central position of the second allocation 32b.

  The UEs served by cell 101 are also configured to transmit additional reference symbols outside of their allocation of data symbols. For example, the second UE 107 has scheduled a second allocation 32b of symbols 7, 8, 9, 11, 12, and 13 and has been inserted within its second allocation 32b, ie, at symbol 10. The reference signal 36 is transmitted. The second UE 107 may also send a reference signal on another reference symbol outside its second allocation 32b. In this case, further reference symbols are transmitted in the first allocation 32a, ie the first 7 symbols of the subframe, eg symbol 3.

  Thus, the first UE transmits the data in the first allocation 32a, ie the 6 data symbols in symbols 0, 1, 2, 4, 5 and 6. Furthermore, the first UE transmits the reference symbol in symbol 3, ie in the resource element corresponding to symbol 3. In some examples, the first UE also transmits a reference symbol 36, eg, in symbol 10, within or adjacent to the data symbol allocations of the different UEs. In this example, subframe 30a includes data allocations for multiple UEs, eg, a first UE and a second UE. Each UE can transmit a reference signal at a time interval corresponding to having data allocation for the entire subframe. Therefore, the reference signal for each UE is transmitted with the conventional periodicity in the subframe, even if the data allocation (and TTI) is only part of the subframe for each UE.

  In this example, both the first UE and the second UE transmit the reference signal 36 on the same symbol, ie on the same resource element. Therefore, the first UE and the second UE share the uplink physical resource. The shared resources are time / frequency resources. The first UE and the second UE independently transmit one or more reference signals. The first UE and the second UE transmit one or more reference symbols at the same time (and on the same subcarrier in frequency in this example).

  The reference symbols 36 of the first UE and the second UE are multiplexed. The multiplexing allows the eNodeB receiving the reference symbols to distinguish between the reference symbols from the first UE and the second UE. For example, each UE is configured to generate and transmit a reference signal to be multiplexed with a reference signal from another UE (eg, a second UE). In some examples, the reference signal is multiplexed by code multiplexing. For example, the first UE is configured to generate and transmit a reference signal with a cyclic shift. Cyclic shift provides multiplexing with other reference signals by, for example, orthogonalizing this reference signal with reference signals from other UEs using various cyclic shifts. In some examples, the reference signal is generated using an orthogonal cover code (OCC) to provide multiplexing.

  Due to the cyclic shift (and OCC), reference signals from multiple UEs are orthogonal to each other. In some examples, the reference signal from each of the UEs in the cell is based on the same base sequence (eg, derived from the cell ID). In some examples, the multiplexed reference signals are transmitted in the same cell, ie, the same base station.

  The second allocation 32b may be considered separate from the first allocation 32a. As such, the first allocation 32a and the second allocation 32b are separate time allocations of physical resources for data symbols. The allocation 32a of the first UE is separate from that of another allocation 32b of the (eg second) UE. In this case, there is no time overlap between data symbols transmitted from separate UEs. The UE may use the same subcarrier but different time resources. In some aspects, only the same frequency resources are used by the first UE and the second UE, ie, in the first allocation 32a and the second allocation 32b. Therefore, the first UE is not given different frequency allocation of resources at the same time as the second UE.

  The separate time physical resource allocation for data symbols is in contrast to the multiplexed reference signal. Reference signals from the UE and another UE have the same time allocation. For example, the same time allocation is the same symbol. For example, the same symbol is the same symbol or symbol period within a slot, subframe, resource block, or resource block pair. The same time allocation may be symbols 3 and 10 of the subframe containing the symbols numbered 0-13. In some examples, the reference signal is transmitted on multiple subcarriers (frequency ranges) with one or more time allocations. Thus, the reference signals are multiplexed in a common time allocation (symbol), while the data symbols are distinct in the time allocation.

  In this case, the first UE data symbol and the second UE data symbol are transmitted within the subframe time period and on the same frequency resource. Reference signals for both the first UE and the second UE are transmitted within the time period and in the same frequency resource. Reference signals for both the first UE and the second UE are transmitted at the same time (ie, in the same symbol), eg, using code multiplexing.

  In some examples, each UE assignment 32a, 32b is used for user data and one or more associated reference symbols. In this example, each of the plurality of UEs uses two reference symbols with a period of 1 ms, ie corresponding to a subframe of LTE Release 8. The TTI of the specific UE allocation 32a, 32b is shorter than the subframe period (1 ms). One or more further UEs are scheduled for allocation (eg, second allocation 32b) in a 1 ms time period. The reference symbols 36 transmitted by the UE with data allocation in the 1 ms time period are multiplexed. Thus, the first UE transmits the same number of reference signal symbols in the subframe, but the number of data symbols (or TTI) is reduced to provide the data allocation for the second UE.

  In some aspects the signal is an uplink signal and / or utilizes SC-FDMA. In this example, the latency is improved because the PUSCH assignment for a particular UE does not cover all SC-FDMA symbols in a 1 ms subframe. Latency is improved by the reduced length of time in TTI (ie, reduced number of symbols).

  The UEs are assigned separate data allocations of time / frequency resources that are not shared with other UEs of the UEs. Among other things, a separate data allocation is a time allocation of physical resources that is separate from one or more further UEs. In some examples, the one or more additional UEs only use the same frequency resource. A separate time allocation does not overlap in time with another UE's time allocation. Separate time allocations may be viewed as separate scheduling of data for two or more UEs. Time allocation refers to the time when transmissions are scheduled (and thus possible) for the UE, not how many data symbols the UE actually transmits in the time allocation. In some aspects time allocations may refer to symbol periods, symbol time periods, and scheduling periods.

  One or more additional UEs may be spatially multiplexed using, for example, MU-MIMO, as described below. Aspects of the disclosure relate to sets of UEs that are not spatially multiplexed with each other, regardless of any spatial multiplexing with additional UEs. A spatially multiplexed UE may share the same time / frequency physical resource with multiple UEs that are multiplexed in a physical resource block or physical resource block pair. Nevertheless, such a spatially multiplexed UE is not referred to as another UE in which data symbols are transmitted in separate time allocations of physical resources or another UE in which reference signals are multiplexed. Such a feature applies to another UE in the set of UEs that are not spatially multiplexed.

  The examples of the present disclosure are applicable to data allocations scheduled to be received on the same antenna port. Thus, the transmitted symbols of the user equipment and the other user equipment described above are scheduled or configured to be received at the same antenna port. Such data allocations may not be spatially multiplexed with each other (ie separate time and frequency resources are scheduled), but may still be spatially multiplexed with data allocations for further UEs.

  A first UE and a second UE with multiplexed reference signals and separate time allocation of data symbols are not frequency multiplexed, ie the first UE and the second UE share the same physical frequency resource To do. The same physical frequency resource may be referred to as a frequency range of a resource block frequency range (for example, 12 subcarriers), a frequency range of a plurality of resource blocks, or another radio frequency range. A UE data symbol is transmitted on the same physical frequency resource as another UE data symbol. In some aspects, the frequency range assigned to the data symbols of the first UE is the same (or overlaps) as the frequency range assigned to the data symbols of the second UE. The multiplexed demodulation reference signal is transmitted by the first UE and the second UE in the same frequency band.

  In FIG. 4, subframe 40 is constructed by transmissions from multiple UEs arranged as shown. In this example, the first data allocation 42a of the first UE has three symbols (eg, SC-FDMA symbols). The data in the first allocation 42a defines the TTI. This reduced TTI (data allocation) reduces latency and allows more UEs to be time multiplexed into subframes.

  In this example, four UEs transmit data in subframes and on the same frequency resource. For example, in subframe 40a, four UEs have a first data allocation 42a, a second data allocation 42b, a second data allocation 42b, labeled "1", "2", "3", and "4", respectively. 3 data allocation 42c and 4th data allocation 42d. The data symbols of the first allocation 42a are transmitted by the first UE and the data symbols of the second allocation 42b are transmitted by the second UE. The data symbols of the third allocation 42c are transmitted by the third UE and the data symbols of the fourth allocation 42d are transmitted by the fourth UE. Multiple UEs (first UE and second UE) may be considered to have separate data allocations in resource blocks, or multiple UEs (first UE to fourth UE) are resource block pairs. May be considered to have a separate data allocation in. The first to fourth UEs may be considered to be scheduled with different time allocations of the same frequency resource. Subsequent subframes 40b may be used to schedule additional UEs, eg, fifth to eighth UEs labeled "5", "6", "7" and "8".

  The subframe time length of 1 ms has two time units (symbols) for the reference signal, for example, the first reference symbol 36a at the position of symbol 3 and the second reference symbol 36b at the position of symbol 10. In some examples, the first reference symbols 36a include multiplexed reference symbols from all UEs that have data allocations in that subframe or physical resource block pair. The second reference symbols 36b also include multiplexed reference symbols from all UEs that have data allocations in that subframe or physical resource block pair. In this case, all reference symbols in a subframe or physical resource block pair are all multiplexed references from a plurality of UEs transmitting data in the physical resource block pair, eg, first UE to fourth UE. Including signal. The reference signal may be transmitted by the UE at times when the data symbols are non-contiguous, such as, for example, the reference signal in symbol 10 for the first UE having data allocation 42a. At a particular time, data for only one UE is transmitted in the physical resource block.

  This allows the receiver to have a high degree of accuracy in subsequent time changes in the channel. This is also the case when a particular UE does not transmit data for the entire length of time, eg over the total length of the subframe.

  In a further example, the particular reference symbol comprises a multiplexed reference signal from only some of the UEs transmitting data in subframes. For example, the first reference symbol 36a includes multiplexed reference signals from only the first UE and the second UE transmitting data in the first allocation 42a and the second allocation 42b, respectively. The second reference symbols 36b include multiplexed reference signals from only the third UE and the fourth UE transmitting data in the third allocation 42c and the fourth allocation 42d, respectively. In this case, the subframe or resource block pair contains data from multiple UEs, and each UE transmits a reference signal at only one symbol position. Therefore, each UE transmits the reference signal only in the symbol time in the subframe, ie, does not transmit in the additional reference signal symbol time in the subframe. This eliminates the need for the receiving side to wait for both reference signals in the subframe time length before processing (demodulation) of user data symbols. For example, the reference signal is directly inserted before or after the data allocation 42a, 42b, 42c, 42d to the UE.

  In some examples, the reference symbols 36a, 36b between the two blocks of user data symbols include reference signals for at least two users assigned to the user data before and after the reference symbols.

  In these examples, multiple UEs are scheduled for separate time allocation of data symbols in slots or physical resource blocks. The reference signal is transmitted by the separately scheduled UE in that slot or physical resource block. Such reference signals are multiplexed. The multiplexed reference signal may be a reference signal for some or all of the UEs scheduled for that slot or physical resource block, or subframe or physical resource block pair.

  The term subframe may be used to indicate a physical resource block pair. Alternatively, the subframes indicate a subframe time interval and a defined frequency range (eg, one or more multiples of 12 subcarriers, or one or more physical resource blocks). May be used for. The frequency range may be the frequency range assigned to the set of UEs that are time multiplexed, as described above. In the frequency domain, only one UE is assigned or transmits data symbols at a particular time.

  The allocation of physical resources according to the present disclosure is based on physical time and frequency resources. Aspects relate to multiple UEs shared in a physical resource block or a pair of physical resource blocks. Multiple UEs may transmit in a frequency range that is larger than one physical resource block or physical resource block pair (eg, 12 subcarriers). The mentioned frequency range or subframe does not result in frequency multiplexing of other UEs. Thus, separate time allocation of physical resources for data symbols refers to separate time allocation for UEs that share the same physical resource block, physical resource block pair, or subframe on a limited frequency band.

  FIG. 5 shows a further example of allocation of physical resources in subframe 50. In this example, two symbols in the data allocation (eg SC-FDMA) are included in the same TTI. Thus, the block of two data symbols may be assigned or scheduled as a TTI for the UE. For example, subframe 50 includes first allocation 52a, second allocation 52b, third allocation 52c, fourth allocation 52d, fifth allocation 52e, and sixth allocation 52f. Each assignment 52a, 52b, 52c, 52d, 52e, 52f is for a distinct first UE to sixth UE in the cell.

  As such, each data symbol has a particular or unique time allocation of physical resources. In some aspects different time resources are assigned to each UE transmitting in a subframe. For example, frequency resources corresponding to one or more physical resource block pairs are used by such UEs. This allocation of physical resources is among other things to the serving cell of the base station (e.g. implemented as eNodeB) of the communication network.

  As described in the example above, each 1 ms subframe includes a first reference symbol 36a and a second reference symbol 36b. In this example, the symbols with the multiplexed reference signal are not necessarily placed next to the data symbols associated with the same UE. Reference symbols are used to multiplex reference signals from multiple users. The reference symbols 36a, 36b used for demodulating the user data may be located before or after the corresponding data (eg, user data). For example, the first allocation 52a of two data symbols is not temporally adjacent to any reference signal, for example the first reference symbol 36a. In this case, the first allocation 52a is scheduled before the first reference symbol 36a. In a further example, the third allocation 52c is not temporally adjacent to the first reference symbol 36a or the second reference symbol 36b and is scheduled after the first reference symbol 36a. Thus, the UE may send a reference signal to be multiplexed after and / or before (non-multiplexed) data symbols. As described above, the first reference symbol 36a and the second reference symbol 36b are all UEs scheduled in the subframe, or some UEs scheduled in the subframe (partially). ) May be included for reference only.

  In some aspects, multiple reference symbols may be combined or interpolated to improve channel estimation at positions for user data symbols.

  In this example, the data symbols for one or more assignments to the UE (ie, in the TTI) are not adjacent to each other in time. For example, the second allocation 52b is divided by the first reference symbol 36a so that the second allocation 52b is both before or after the first reference symbol 36a in time. The second allocation 52b (or TTI) of data symbols is at symbols 2 and 4. The reference symbols 36a, 36b are in conventional positions in a 1 ms subframe. In some aspects, such divided data allocations 52b, 52e have a higher latency of the transmitted data than a contiguous data allocation, eg, the third allocation 52c. The third allocation 52c is after the reference signal 36a, so the eNodeB does not have to wait for the decoding of the data. The eNodeB waits until the reference signal 36a at symbol 3 is received before it can decode the data at the first allocation 52a.

  FIG. 6 shows a subframe 60 with an alternative mapping of data symbols. In this example, the data (eg, SC-FDMA) symbol is shifted one symbol in time as compared to the example in FIG. For the example of FIG. 5, two data symbols are transmitted in the TTI or data allocation to the UE every one subframe. In the example of FIG. 6, two data symbols from one UE are located temporally adjacent to each other. Therefore, the TTI for the UE is not divided around the reference signal.

  The first to fifth assignments 62a, 62b, 62c, 62d, 62e are transmitted in the first subframe 60a. The first allocation 62a starts, for example, in symbol 1 after the start of the subframe. The reference symbols are located at conventional positions within the subframe, ie symbols 3 and 10. The subframe 60 is arranged such that none of the data allocation is divided into two non-contiguous parts by the reference signal. For example, the second allocation 62b is not divided by the first reference symbol 36a, as illustrated in FIG. Instead, the second allocation 62b follows the first reference symbol 36a.

  In this example, the data symbols for one UE can be divided between the first subframe 60a and the subsequent second subframe 60b, or a physical resource block pair. In this example, the data symbol of the sixth allocation 62f is divided between the subframes 60a and 60b. The subframes 60a and 60b may be referred to as a subframe pair or an adjacent resource block pair. Thus, a separate physical resource allocation of data symbols is a separate time allocation in a pair of subframes of communication for another user equipment. The subframe pair refers to the time period of the subframe pair, eg, 2 ms. This example is described for a 1 ms LTE Release 8 subframe. The reference signal is multiplexed as described in either example above.

  FIG. 7 shows a further example of mapping of data symbols to subframes 70. In this example, only one data symbol is included in the same TTI. Each UE is assigned a single data symbol for each subframe or physical resource block pair. For example, the first data allocation 72a for the first UE has only one symbol in the subframe. In this example, twelve UEs have subframe time periods and separate time allocations for data in the same physical frequency resource. The first UE further transmits one or more reference signal symbols 36 in the subframe. Reference signals of multiple UEs are multiplexed on the same reference symbol. The reference signals are multiplexed as described in any of the examples above, eg, all UEs transmitting in a subframe transmit in all reference signal symbols or in only one reference signal symbol. Therefore, each reference signal symbol is a multiplex transmission scheme of all or some of the reference signals from the UE transmitting data in the subframe or physical resource block pair.

  In any of the described examples, the reference signal is code multiplexed onto the same symbol. For example, the reference signal is multiplexed using cyclic shift (and OCC).

  Up to 12 different UEs, for example 3GPP TS 36.211, "Physical Channels and Modulation" technical specifications, 3rd Generation Partnership Project, Specification Group Radio Access Network, Enhanced Universal Terrestrial Radio Access (E-UTRA), V12.5. .0. , Http: // www. 3 gpp. In org / ftp / Specs / archive / 36_series /, it is possible to code multiplex on the same symbol by using a cyclic shift, for example as defined in the LTE Release 8 specification. The cyclic shift may be considered as a linear phase rotation in the frequency domain of the reference signal.

  The UE may be configured to use different time cyclic shifts of the reference signal within the same SC-FDMA symbol. This cyclic shift corresponds to the known cyclic time delay of the reference signal. If this cyclic time delay is greater than the delay spread of the radio channel, the receiver can estimate the channels of different users separately.

  Alternatively or in addition, reference signals 36 from multiple UEs transmitting in the same slot, subframe, physical resource block, or physical resource block pair may be frequency multiplexed. For example, the reference signal 36 in any example can be multiplexed using a frequency comb. The reference signal may be considered to repeat at a predetermined frequency or subcarrier spacing. For example, a "repetition factor" of 6 can be used so that the reference signal from the UE is transmitted on any 6th carrier. In some examples, LTE Release 8 cell-specific reference signal (CRS) designs are used, for example, where appropriate for radio channel coherence bandwidth. In some examples, frequency multiplexing is done on the same frequency resources used by the data allocation. A plurality of frequency-multiplexing demodulation reference signals are simultaneously transmitted, for example, in symbol 3 and / or symbol 10 in a subframe.

  In some aspects, if multiple reference signals are multiplexed by different frequency combs, the number of reference signals multiplexed by the cyclic shift is reduced by the same amount. In some examples, frequency combs and cyclic shifts are combinable and configured to have low interference between different reference signals corresponding to different cyclic shifts and combs.

  In some aspects a plurality of demodulation reference signals are multiplexed by code multiplexing or by frequency multiplexing. Reference signals for multiple UE sets are not multiplexed by spatial multiplexing. The reference signals for this set of UEs are multiplexed by code or frequency multiplexing. For this set of UEs, each UE has a separate time allocation of data symbols. The separate time allocations of data symbols are for frequency ranges (eg, resource blocks) used only by that set of UEs. Frequency multiplexing of reference signals is performed within a frequency band, or resource block, or resource block pair used by a set of UEs. In some aspects, the UEs in the set of UEs may (or may not) be spatially and / or frequency multiplexed by one or more additional UEs. Aspects of the disclosure apply to a set of UEs in a limited frequency range (eg, resource block frequency range) and to a set of UEs that are not spatially multiplexed by other UEs in the set.

  In some aspects, the reference signal is multiplexed using both code multiplexing (eg, cyclic shift / OCC) and frequency multiplexing (eg, using a frequency comb). The UE is configured with one or more parameters such that the interference between different reference signals corresponding to different codes (eg cyclic shift) and frequencies (eg comb) is low.

  Multiplexed reference signals from different UEs may be considered to be transmitted in the same basic time unit of subframe. In this case, resource elements that share the allocated time base unit are used for multiple reference symbols. The multiplexed reference symbols are from the UE that is also transmitting the data in the resource block or resource block pair. In some examples, the resource block or resource block pair corresponds to a time frequency physical resource, eg, 7 or 14 symbols in the time domain and 12 subcarriers in the frequency domain.

  In some aspects reference signals are transmitted in physical resources along with data symbols. Therefore, the reference signal is transmitted in the same resource block or subframe as the data symbol transmitted from the UE, or a time adjacent resource block or subframe. For example, the frequency bandwidth of the reference signal (that is, the subcarriers used) is the same as the data from the UE. In some aspects reference signals are always transmitted with or in physical resources associated with data symbols.

  In the above example, the reference symbol is placed in the central symbol (eg, SC-FDMA symbol) of the slot or resource block. Therefore, the reference symbol is at the center of time of the slot. Alternatively, reference symbols may be inserted at different locations without changing the principles of the present disclosure. The use of the reference signal in the middle of the slot allows the base station (eg, eNodeB) to use the reference symbol for mixed interference measurement of legacy Release 8 UEs and UEs operating according to the methods of this disclosure. .. The location of the reference signal as the central symbol, as also used by legacy UEs, means that the reference symbol represents a worst case interference scenario.

  When the TTI length is shortened (ie, less than the length of the slot or subframe), the one or more reference signals transmitted in each TTI have a relatively increased overhead, and a corresponding increase. Represents a decrease in data rate. For example, in a two-symbol TTI, only half of the symbols are available for data transmission compared to 12 of the 14 symbols (12 data symbols, 2 reference symbols) used in LTE Release 8. Yes (1 data symbol and 1 reference symbol). Furthermore, for TTI of one symbol, the current uplink (SC-FDMA) structure cannot be used because the symbol can be used for either reference signal or data, but not both. The multiplexing of reference symbols over unmultiplexed data symbols reduces overhead or increases data rate. Multiplexing of reference signals from different UEs is considered to allow the same number of reference symbols to be used by each UE, even if the TTI or transmission length within a subframe in that data allocation is reduced. May be. In some examples, the TTI is considered the time interval from the first transmitted data symbol to the last transmitted data symbol such that the data symbols are jointly channel coded. This may exclude reference symbols, eg, reference signal symbols that are not temporally continuous with the associated data symbol. The reference signal (DM-RS) is still transmitted by the UE and associated with the data, and the example of the present disclosure reduces latency without changing the reference signal transmission timing.

  FIG. 8 illustrates a further example of subframe 80 of the present disclosure. As described above in FIG. 7, resource allocation causes the UE to transmit reference signal 36 and data symbols in subframe 80, where the reference signals (not the data symbols) are multiplexed. The data allocation for each UE in the subframe is one symbol period, for example, the first data allocation 82a has one symbol length (TTI). In this example, the reference symbol 36 assigned to the UE is before (ie, transmitted before) the data from the particular UE.

  For example, for the third data allocation 82c for the third UE, the closest reference signal is the first reference symbol 36a immediately after the third data allocation 82c. In this example, the reference symbol 36a is not used by the third UE. Instead, the third UE uses reference symbols (not shown) that precede earlier frames. For the fourth data allocation 82d, the preceding reference symbol 36a is used to transmit the reference signal. It is also the closest reference symbol in time. Reference signals from UEs having data allocations for symbols 4-9 (4th UE to 9th UE) are multiplexed into a single reference signal 36a. Reference signals from UEs having data allocations for symbols 11 to 2 (10th UE to 14th UE) of the subsequent subframes are multiplexed into a further single reference signal 36b. The data allocation and associated reference signals may be considered to be located on a pair of subframes, two resource blocks, or two physical resource block pairs.

  Channel estimation is always available for how reference symbols are transmitted before data symbols. Therefore, there is no additional latency before the channel estimate is obtained.

  This is an alternative that can be used in any of the above examples of a UE that uses the reference symbol that is closest (in time) to the data symbol, regardless of whether the reference symbol is before or after the data symbol. This is in contrast to the policy. In some examples, the UE may send reference signals in all reference signal symbol assignments so that channel estimates close to user data are available. The UE is also prepared to receive and process possible reception of user data.

  The reference signal can be transmitted in some symbols (eg, SC-FDM symbols) in the slot or subframe period. As the number of symbols used for reference signals increases, more users can spend more reference signal overhead and can be multiplexed.

  The use of the closest reference symbol allocation for the data results in, among other things, a high quality channel estimation in the fading channel. For slow UEs, the fading may be non-limiting and it is effectively available to send the reference symbol before the data. In some examples, the bandwidth of the reference signal and the bandwidth of data transmission on the physical uplink channel (eg, PUSCH) are not the same. The UE may be configured to transmit the reference signal before (dynamically) configured to transmit data, eg, on the PUSCH. In such cases, the reference signal may cover a different (eg, larger) bandwidth compared to the actual data (eg, PUSCH) transmission.

  In MU-MIMO, several UEs share the same time and frequency resources. An example of this application is applicable to MU-MIMO, eg uplink MU-MIMO. In this case, multiple user equipments are spatially multiplexed (spatial division multiple access).

  For any of the described examples, multiple UEs can transmit within the same symbol of time / frequency resources. This requires several receive antennas (eg at the base station), a receiver capable of multi-user detection in demodulation, and a radio channel that is rich enough to separate the user signals in demodulation. Within this demodulation, the radio channel for each user has to be estimated. The reference signal is a symbol (eg, SC-FDM symbol) at a particular time in a subframe when using MU-MIMO spatial multiplexing of users in a manner similar to that described above for user time multiplexing. ) Is multiplexed. Here, spatially multiplexed users may use different cyclic shifts or frequency combs for different reference signals.

  In the UL MU-MIMO embodiment, the user data is transmitted from the part of the transmitter that transmits the reference signal in the same SC-FDMA symbol.

  In some examples, user equipment communication in a communication network is based on frequency division duplex (FDD). The examples of this disclosure may be used in a time division duplex communication network.

  In some examples, the reference signal is used by the base station for channel estimation for coherent demodulation of the uplink physical channel. The demodulation reference signal can be transmitted only on the channel used for PUSCH or PUCCH, for example. The reference signal covers at least the same frequency range as the corresponding physical channel. In some aspects a demodulation reference signal may be considered to be associated with a data symbol when the demodulation reference signal is used to demodulate the data symbol. Thus, examples of this disclosure relate to related demodulation reference signals and data symbols. Related reference signals and data are sent from the same UE. The associated demodulation reference signal and data symbol may be transmitted in adjacent symbol periods, or the demodulation reference signal and data symbol may be in non-adjacent symbol periods. The associated demodulation reference signal and data symbols may be in the same slot of the subframe time period. In some examples, the associated demodulation reference signal and data symbols are transmitted over a period of two subframes.

  The example is applicable to UEs communicating with the same base station. In this case, the UE that multiplexes the reference signal is transmitting the reference signal and the data symbol to the same base station (eg, eNB). In some examples, the base stations used for the uplink and downlink are different. In this example, the base station used to signal user equipment (on the downlink) is different than the base station receiving the signal on the uplink. This example can be implemented if the first base station has a better downlink than the second base station, but the uplink is better than the second base station (compared to the first base station). good.

  Examples of the present disclosure may include reducing data transfer time and control signaling (e.g., by reducing TTI length) and / or control signaling processing time (e.g., for a UE to process a grant signal). The reduction of the time) leads to the reduction of packet latency.

  FIG. 9 shows an example node configuration of a base station or eNB 401 that may perform some of the example embodiments described herein. Base station 401 can comprise a wireless circuit or communication port 410 that can be configured to receive and / or transmit communication data, instructions, and / or messages. It should be appreciated that the wireless circuit or communication port 410 can be configured as any number of transmit / receive, receive, and / or transmit units or circuits. It should be further understood that the wireless circuit or communication port 410 may be in the form of any input or output communication port known in the art. The wireless circuit or communication port 410 may include RF circuitry and baseband processing circuitry (not shown).

  Base station 401 can also include a processing unit or circuit 420 that can be configured to perform scheduling for configuring UEs according to any example of the present disclosure. The processing circuit 420 may be any suitable type of computing unit, such as a microprocessor, digital signal processor (DSP), field programmable gate array (FPGA), application specific integrated circuit (ASIC), or any other form. Circuit may be used. The base station 401 may be any suitable type of computer readable memory and may further include a memory unit or circuit 430, which may be of volatile and / or non-volatile type. The memory 430 is configurable to store received, transmitted, and / or instrumented data, device parameters, communication priorities, and / or executable program instructions. In some examples, base station 401 further comprises a network interface 440 for communicating with one or more additional base stations and / or core networks.

  FIG. 10 illustrates an example node configuration for a UE or wireless terminal 505 that may perform one or more of the described examples. The wireless terminal 505 may be user equipment, machine-to-machine type device, or any other device capable of communicating with a communication network. The wireless terminal 505 can include a radio circuit or communication port 510 that can be configured to receive and / or transmit communication data, instructions, and / or messages. It should be appreciated that the wireless circuit or communication port 510 may be configured as any number of transmit / receive, receive, and / or transmit units or circuits. It should be further understood that the wireless circuit or communication port 510 may be in the form of any input or output communication port known in the art. The wireless circuit or communication port 510 can include RF circuitry and baseband processing circuitry (not shown).

  The wireless terminal 505 may also include a processing unit or circuit 520 that may be configured to obtain a downlink broadcast transmission, eg, to receive signaling to configure any example of this disclosure. The processing circuit or unit is configurable to transmit the data symbols and the multiplexed reference signal according to any example. The processing circuit is configured to transmit, via the communication circuit, a subframe including the reference signal and the user data multiplexed in separate symbols. The device may be configured differently, as described above.

  The processing circuit 520 may be any suitable type of computing unit, such as a microprocessor, digital signal processor (DSP), field programmable gate array (FPGA), application specific integrated circuit (ASIC), or any other form. Circuit may be used. The wireless terminal 505 may be any suitable type of computer readable memory and may further include a memory unit or circuit 530, which may be of volatile and / or non-volatile type. The memory 530 is configurable to store received, transmitted, and / or instrumented data, device parameters, communication priorities, and / or executable program instructions.

  FIG. 11 is a flow diagram 110 illustrating an example of operations that may be taken by the wireless terminal 105; 505 as described herein to transmit a reference signal. It should be understood that these operations need not occur sequentially, either may occur simultaneously. Furthermore, it should be understood that not all of the acts need to be performed. The example operations may be performed in any order and in any combination.

  At 111, the UE determines multiplexing information for the reference signal. The multiplexing information may be received in signaling from the network or may be determined by the UE based on internally stored information or one or more measured parameters. The multiplexing information may be code multiplexing (eg, cyclic shift and / or OCC) for use, and / or frequency multiplexing configuration information. Such resources are scheduled by the eNodeB or other network entity. In some examples, the signaling is similar to the known signaling used for cyclic shift in MU-MIMO. In some aspects a UE is configured to receive a scheduling for transmission of data from a base station. The received scheduling is for a separate time allocation of data symbol transmissions to data symbol transmissions of other UEs using the same frequency resource, where the UEs transmit multiplexed reference signals.

  At 113, the UE transmits a reference signal. The reference signal is transmitted on the determined time / frequency resource. The transmitted reference signal is multiplexed with reference signals from other UEs. This allows the receiving base station to separate and process the reference signals from each UE independently.

  At 115, the UE transmits data symbols. Transmission of the data symbols occurs before and / or after the reference signal used to demodulate the data symbols. Data symbols are transmitted on scheduled time resources that are separate from time resources scheduled for other UEs using the same frequency and the same receive antenna port.

  FIG. 12 is a flow diagram 120 illustrating example operations that may be taken by a base station 103, 401 as described herein to schedule uplink transmissions of reference signals and data symbols. It should be understood that these operations need not occur sequentially, either may occur simultaneously. Furthermore, it should be understood that not all of the acts need to be performed. The example operations may be performed in any order and in any combination.

  At 121, the base station receives a first reference signal from the first UE. At the same time, at 123, the base station receives the multiplexed second reference signal from the second UE. The base station demultiplexes the first reference signal and the second reference signal by, for example, code demultiplexing and / or frequency demultiplexing.

  At 125, the base station receives the first data symbol. The first data symbol is received in a time allocation of subframes associated with the first UE.

  At 127, the base station receives the second data symbol. The second data symbol is received in a separate time allocation of subframes associated with the second UE. The second data symbol is received only after the reception of the first data symbol is completed.

  At 129, the base station processes the received reference signals and data symbols. For example, the base station demodulates the first data symbol and the second data symbol based on the associated received reference signal. The channel estimation derived from the reference signal can be used for the demodulation.

  In a further aspect, the base station sends the multiplexing information to the first UE and the second UE to provide multiplexed reference signals for the first UE and the second UE. The transmitted information results in a multiplexed reference signal that is split by the base station.

  In a further aspect, the base station determines scheduling for multiple UEs served by the base station. The base station decides on the scheduling according to any example, for example a common time allocation for multiple UEs to send demodulation reference signals, and each UE to send related data separately. A separate time allocation for each subframe (or multiple subframes) to The base station is configured to send the first UE data and the second UE data, and / or corresponding scheduling information to the first UE and the second UE for scheduling reference signal allocation. ..

  The present disclosure may, of course, be carried out in other ways than those specifically set forth herein without departing from the essential characteristics of the present disclosure. This embodiment is to be considered in all respects as illustrative and not restrictive.

  One of ordinary skill in the art would understand that the embodiments herein generally include methods performed by communication devices in wireless communication networks. The method is for transmitting a reference signal (eg DM-RS) along with data (eg user data) on a PUSCH in an LTE network. The method comprises, for example, generating and transmitting a reference signal suitable for being multiplexed orthogonal to a reference signal from another UE transmitting on the same symbol (ie on the same time and frequency physical resource). Can be included.

  One or more embodiments herein also include corresponding communication devices, computer programs, and computer program products.

  The communication device can include, for example, communication circuitry configured to send and receive wireless communications, and processing circuitry communicatively coupled to the communication circuitry. The processing circuitry is configurable to determine the allocation of data symbols and the configuration of reference signals and / or to transmit data symbols and reference signals. The device can be configured as described above. The computer program includes instructions that, when executed by at least one processor of the device, cause the device to perform any of the methods herein.

  The carrier contains the computer program described above, which is one of an electronic signal, an optical signal, a wireless signal, or a computer-readable storage medium.

  Numerous implementations can benefit from the reduced latency provided by the examples of this disclosure. For example, aspects can enhance perceived quality of experience, examples of which include games, real-time applications such as VoLTE / OTT VoIP, and multi-party video conferencing. Additional applications that are delay critical may also utilize aspects of the present disclosure, such as remote control / driving of vehicles, augmented reality applications such as in smart glass, or specific machine communication that requires low latency.

  It should also be noted that the reduced latency of data transport can indirectly provide faster radio control plane procedures such as call setup / bearer setup with faster transport of higher layer control signaling.

  Any reference to a subframe may refer to the time period of the subframe, eg 1 ms. References to subframes may refer to only some of the frequency resources of a subframe, eg, the frequency resources of a resource block or resource block pair. Such frequency resources are shared by the set of UEs served by the cell, in some examples, some of the UEs served by the cell. Moreover, UEs that operate using different frequency resources are not part of the set of UEs that are defined to operate in accordance with the disclosure herein.

  Aspects of the present disclosure are applicable to downlink and / or device-to-device transmission, and also to the uplink. For example, any reference to the uplink from the UE to the base station can be reversed to refer to the downlink from one or more base stations to the UE. For example, aspects that provide low PAPR for the downlink rather than the uplink, and / or device-to-device transmissions can utilize the single carrier described.

Aspects of the disclosure are described as applicable to SC-FDMA. Alternatively, any example is applicable for use in Orthogonal Frequency Division Multiple Access (OFDMA).

Claims (20)

A method in a user equipment for transmitting a demodulation reference signal in a communication network, comprising:
Determining multiplexing information about the demodulation reference signal,
Transmitting the demodulation reference signal using the multiplexing information in the same time allocation as the demodulation reference signal of another user equipment;
Transmitting data symbols associated with the demodulation reference signal in a separate time allocation of physical resources and in the same physical frequency resource for time allocation of data symbols of the different user equipment. ,Method.   The separate physical resource allocation of the data symbols is a separate time allocation of subframes, slots, physical resource blocks, physical resource block pairs, or pairs of subframes of communication to another user equipment. The method described.   The user equipment transmits the reference signal and the data symbol in a cycle of a slot, a subframe, or two subframes, and the reference signal is another user equipment in the slot, subframe, or two subframes. 3. The method of claim 1 or 2, wherein the user equipment transmits data symbols in separate time allocations of slots, subframes, or the periods of two subframes when multiplexed with a reference signal of.   Determining the multiplexing information for the reference signal comprises determining information for code multiplexing the reference signal with one or more reference signals from the other user equipment. 4. The method according to any one of 3 to 3.   5. Any one of claims 1 to 4, comprising generating the reference signal with a cyclic shift determined to result in code multiplexing with the one or more reference signals from the another user equipment. The method described in.   6. The method of any one of claims 1-5, comprising generating the reference signal at frequency intervals to provide frequency multiplexing with the one or more reference signals from the another user equipment. Method.   7. The method according to any one of claims 1 to 6, wherein the data symbols are transmitted within a transmission time interval (TTI) that is less than one subframe and / or less than one millisecond.   8. The method of claims 1-7, wherein the data symbols are transmitted with a transmission time interval (TTI) of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or 13 symbols. The method according to any one of claims.   9. The method according to any one of claims 1-8, wherein the communication is a PUSCH communication and / or the data symbols are SC-FDMA symbols.   10. The method according to any one of claims 1-9, wherein the user equipment is communicating as part of a multi-user Multiple In Multiple Out (MU-MIMO) communication with yet another user equipment.   11. The method of any of claims 1-10, wherein the transmitted symbols of the user equipment and the other user equipment are scheduled to be received on the same antenna port. A method in a base station for communicating with a user equipment in a communication network, comprising:
Receiving a first reference signal from a first user equipment;
Receiving a second reference signal from a second user equipment,
The first reference signal and the second reference signal are multiplexed,
Receiving a first data symbol from the first user equipment;
Receiving a second data symbol from the second user equipment.
The method, wherein the data symbols from the first user equipment and the second user equipment are received in separate time allocations of physical resources and on the same physical frequency resource.   Signaling to the first user equipment and the second user equipment with multiplexing information about the first reference signal and the second reference signal, respectively, and / or the first user equipment and 13. The method of claim 12, further comprising signaling to the second user equipment with information regarding a separate time allocation of physical resources for data symbol transmission.   The method according to claim 13, wherein the multiplexing information is code multiplexing information and / or frequency multiplexing information.   The first reference signal and the second reference signal, and the first data symbol and the second data symbol are in a single slot, a physical resource block, a subframe, a physical resource block pair, or The method according to any one of claims 12 to 14, wherein the method is received in adjacent subframes or physical resource block pairs. A user equipment configured to transmit a demodulation reference signal in a communication network,
A processing circuit configured to determine multiplexing information about the demodulation reference signal,
A radio circuit configured to transmit the demodulation reference signal using the multiplexing information in the same time allocation as the demodulation reference signal of another user equipment,
The radio circuit transmits data symbols associated with the demodulation reference signal in a separate time allocation of physical resources and in the same physical frequency resource with respect to the time allocation of data symbols of the different user equipment. User equipment configured as follows.   17. The user equipment of claim 16, wherein the user equipment is configured to code and / or frequency multiplex a demodulation reference signal with the demodulation reference signal of the another user equipment. A base station configured to communicate with user equipment in a communication network,
A radio circuit configured to receive a first reference signal from a first user equipment and a second reference signal from a second user equipment,
The first reference signal and the second reference signal are multiplexed,
A radio circuit is configured to receive a first data symbol from the first user equipment and a second data symbol from the second user equipment,
The base station, wherein the data symbols from the first user equipment and the second user equipment are in separate time allocations of physical resources and in the same physical frequency resource.   Of physical resources for data symbol transmission to determine multiplexing information for the first reference signal and the second reference signal, and / or by the first user equipment and the second user equipment. A processing circuit configured to determine a separate time allocation, said wireless circuit relating to such multiplexing information and / or said separate time allocation for said first user equipment and said second user equipment. The base station according to claim 16, wherein the base station is configured to transmit information. A computer program product configured to perform the method according to any one of claims 1 to 14 when running on a computer.

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