JP7107913B2 - Reference signals in communication networks - Google Patents

Description

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

Packet data latency is one of the performance metrics regularly measured by vendors, operators, and even end users. Latency measurements are taken at all stages of the radio access network system life, for example when validating 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 latency reduction. Lower packet data latency increases the number of possible transmissions within a given delay bound. Therefore, higher block error rate (BLER) targets may be used for data transmission, freeing up 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 (0.5ms) in the time domain and 12 subs in the frequency domain. Corresponds to career. Resource blocks are numbered in the frequency domain starting from 0 at one end of the system bandwidth.

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

Data is created by higher layers and a user equipment (UE) modem needs to send a scheduling request (SR) to an evolved NodeB (eNB). The eNB processes this SR and responds with a grant so the uplink data transfer can start.

FIG. 1 shows an LTE Release 8 mapping of user data symbols and reference signals within two physical uplink shared channel (PUSCH) subframes 10, labeled first subframe 10a and second subframe 10b. Here is an example. Subframe 10 is in time/frequency structure. Each row 11 corresponds to a different frequency subcarrier (eg, separated by 15 kHz) and each column 12 corresponds to a symbol interval in a different time or basic time unit 12 . A resource element 13 consists of one subcarrier during one symbol. Each subframe 10a, 10b contains 14 symbols in time (for a normal length cyclic prefix) labeled 0-13. Each of the subframes 10a, 10b is organized in two slots of 7 symbols each and multiple subcarriers in frequency. A resource block (or physical resource block) is defined as 1 slot in time and 180 kHz in frequency (eg, 12 subcarriers). A resource block pair or 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, a physical resource block has a limited frequency range (eg, one set of 12 subcarriers). Data for only one UE is sent in physical resource block pairs.

As specified 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 middle of each slot as shown in FIG. The numbers in the resource element grid refer to an exemplary transmission time interval (TTI) during which transport blocks are transmitted. Each column indicates the resource element used to transmit the symbol. The numbers in the bottom part of FIG. 1 indicate the index of the uplink symbol, in this example within the LTE Release 8 subframe.

Reference signal 'R' 16 is inserted at SC-FDMA symbol number 3 and symbol number 10 in the subframe. In the first subframe 10a, data symbols are transmitted on all symbols except for 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 "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 used for channel estimation of the data symbols 13 of the first subframe 10a. 2 may be used for channel estimation of data symbols 13 of subframe 10b.

For single carrier formats such as those used in the LTE uplink, each signal is spread over multiple resource elements and 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 is defined, for example, in 3GPP TS 36.211, "Physical Channels and Modulation" technical specification, 3rd Generation Partnership Project, Specification Group Radio Access Network, Enhanced Universal Terrestrial Radio Access (E-UTRA), V12.5 .0, is based on OFDM in the downlink and DFT-spread OFDM, also called Single-Carrier Frequency Division Multiple Access FDMA (SC-FDMA) in the uplink. Signals to be transmitted on the uplink are precoded by DFT, mapped to assigned frequency intervals, transformed to the time domain, concatenated with a cyclic prefix, and finally transmitted over the air. Symbols constructed by DFT, mapping, IFFT, and CP insertion are denoted as SC-FDMA symbols. Within LTE Release 8, a TTI is constructed with 14 such SC-FDMA symbols for a normal 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. A low PAPR allows the transmitter to be equipped with simpler and less energy consuming radios, which is important for user devices where cost and battery consumption are key issues.

The reference signal represents overhead in which no user data is transmitted. Increasing user data transmission is beneficial to increase the data transfer rate. Reduced latency is also advantageous.

A first aspect of the present disclosure provides a method in a user equipment for transmitting demodulation reference signals 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 the demodulation reference signal for another user equipment. . The method comprises transmitting data symbols associated with demodulation reference signals in separate time allocations of physical resources and on the same physical frequency resources relative to time allocations of data symbols of said different user equipment. Including further.

Hence, the overhead represented by the reference signal is reduced. This is particularly advantageous when the TTI of the user data is reduced, eg, to less than one subframe or less than one slot in duration.

A second aspect of the present disclosure provides a method in 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 a first user equipment and receiving a second data symbol from a 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 resources.

A third aspect of the present disclosure provides user equipment configured to transmit demodulation reference signals in a communication network. The user equipment uses processing circuitry configured to determine multiplexing information for a demodulation reference signal and a demodulation reference signal using the multiplexing information in the same time allocation as the demodulation reference signal for another user equipment. a radio circuit configured to transmit a A radio circuit is configured to transmit data symbols associated with demodulation reference signals in separate time allocations of physical resources and on the same physical frequency resources relative to the time allocations of data symbols of said different user equipments. configured to

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

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

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

FIG. 1 illustrates the prior art allocation of reference signals and data to subframes of transmission; 1 illustrates an example network in accordance with examples of this disclosure; FIG. [0014] FIG. 4 is a diagram illustrating example assignments of reference signals and data symbols to subframes of transmission, in accordance with one aspect of the present disclosure; FIG. 4 illustrates further examples of allocation of reference signals and data symbols to subframes of transmission, in accordance with one aspect of the present disclosure; FIG. 4 illustrates further examples of allocation of reference signals and data symbols to subframes of transmission, in accordance with one aspect of the present disclosure; FIG. 4 illustrates further examples of allocation of reference signals and data symbols to subframes of transmission, in accordance with one aspect of the present disclosure; FIG. 4 illustrates further examples of allocation of reference signals and data symbols to subframes of transmission, in accordance with one aspect of the present disclosure; FIG. 4 illustrates further examples of allocation of reference signals and data symbols to subframes of transmission, in accordance with one aspect of the present disclosure; 1 shows a schematic overview of a base station according to examples of this disclosure; FIG. FIG. 2 shows a schematic overview of user equipment in accordance with an example of this disclosure; [0013] Figure 4 illustrates an example method in user equipment according to examples of this disclosure. [0014] Figure 4 illustrates an example method in a base station according to examples of this disclosure;

Examples of this disclosure relate to multiplexing reference signals from or to several transmitters into the same symbol, while user data from or to different transmitters are in separate symbols. sent. The symbols may be, eg, SC-FDMA symbols on the uplink from multiple UEs.

The amount of overhead in resource allocation is significantly reduced by multiplexing reference signals from (or to) multiple UEs onto the same symbol. User data from one UE, on the other hand, does not experience interference from other UEs because each UE has a dedicated symbol (eg, SC-FDMA symbol) for user data. Single-carrier properties of (eg, uplink) transmission may be preserved, which positively impacts device cost and power consumption.

FIG. 2 shows an example of a communication network 100, which embodiment relates to transmission of reference signals, eg, demodulation reference signals (DMRS) or signaling information. In some examples, transmission of reference signals is a multiplexing 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, eg, base stations 103 serving cell 101 . The base station 103 is any radio base station, NodeB, e.g. base stations, such as other network units in . Wireless carrier 102 may also be referred to as a carrier, wireless channel, channel, communication link, radio link, or link. Base stations 103 can be of different classes, e.g. macro base stations, e.g. eNodeBs, or low power base stations, e.g. home eNodeBs, pico base stations or femto base stations, based on transmit power and also cell size. may be of Although FIG. 2 shows base station 103 serving one cell 101 , base station 103 can serve more than one cell 101 . Communication network 100 may further include one or more additional user equipment, eg, second user equipment 107 and third user equipment 109 . In some embodiments, second user equipment 107 and second user equipment 109 are in the same cell 101 and served by the same base station 103 as first user equipment 105 .

Communication network 100 may be partitioned into cells, such as cell 101 . Accordingly, communication network 100 is sometimes referred to as a cellular communication network. A cell is a geographical area in which a base station 103 serving cell 101 provides radio coverage to user equipment 105 residing in cell 101 . Cell 101 may be, for example, a microcell typically covering a limited area, a picocell typically covering a small area, a femtocell typically designed for use in a home or small business, Or they may be of different sizes, such as macrocells, which typically provide greater coverage than microcells.

User equipment 105 residing in cell 101 and served by base station 103 can now communicate with base station 103 over wireless carrier 102 . Data streams are communicated between base station 103 and user equipment 105 over radio channel 102 in a layered approach. Examples of layers include physical layer, data link layer, network layer, transport layer, session layer, and so on.

User equipment 105 may be 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, a mobile phone, smart phone, personal digital assistant (PDA). ), laptop, MP3 player or portable DVD player (or similar media content device), digital camera, or even a stationary device such as a PC. PCs may be connected via mobile stations as end stations for broadcast/multicast media. The user equipment 105 may be, for example, an electronic photo frame, a heart monitor, an intrusion monitor or other surveillance equipment, a weather data monitoring system, a communication device embedded in a vehicle, automobile or transport communication equipment, and the like. User equipment 105 is referred to as UE in some of the figures. A 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.

Note that the wireless carrier 102 between the base station 103 and the user equipment 105 may be of any suitable type, including either wired or wireless links. Carrier 102 may use any suitable protocol depending on the type and level of layers, for example, as dictated by the Open Systems Interconnection (OSI) model, as will be understood 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, such as those 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 subframe 30 of physical transmission resources scheduled for multiple UEs. Subframe 30 corresponds to LTE Release 8 as described above, except where noted otherwise. Symbols 13 correspond to user data or reference signals and, in some examples, control data. The term subframe is sometimes used to denote the time period of a physical resource block pair. Alternatively, a 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 pairs.

Information sent over the air interface is called payload. A subframe (eg, a PUSCH subframe) can carry the payload as well as any control information necessary to decode the payload, such as transport format indicators and MIMO parameters. Such control data is multiplexed with the payload before DFT spreading. Both payload and control data are sometimes referred to as user data or data as distinct from reference signals.

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 on resources less than 14 symbols or 1 ms duration. In this example, the first subframe 30a is designated for two UEs, eg, a first UE 105 and a 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 includes 7 symbols in time and the second allocation 32b also includes 7 symbols in time. In this example, 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, the PUSCH assignment does not cover all SC-FDMA symbols in the 1 ms subframe. In some aspects, the frequency resource allocation is as conventionally known, eg, a resource block has 12 subcarriers. Aspects of this disclosure are also applicable to transmissions on the physical uplink control channel (PUCCH).

Each allocation 32a, 32b is a transmission time interval (TTI) for a different UE. The number '1' in the symbols of the first allocation 32a represents data symbols for the first UE and the number '2' in the symbols of the second allocation 32b represents data (e.g. user data) symbols 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-RS corresponding to the reference signals described above.

FIG. 3 shows eight subcarriers (ie, rows) labeled to indicate data symbols or reference symbols. The number of rows displayed is merely illustrative 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 (e.g. eNodeB) to estimate the channel, timing and frequency errors for use in demodulating and decoding user data. , and/or to estimate uplink channel quality. The eNodeB may use the Sounding Reference Signals (SRS) separately, eg for uplink frequency selection 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 a 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 a reference signal in the second allocation 32b, ie in symbol 10 of the first subframe 30a. Out of data symbol time may refer to time of allocation to another user or to a different resource block, subframe or symbol that is not contiguous in time with the UE's allocated resources for user data. . This allows the UE to follow the time variations of the radio channel outside the time of this data symbol allocation. In this situation, the reference signal 36 is at the center position of the first allocation 32a and at the center position of the second allocation 32b.

UEs served by cell 101 are also configured to transmit additional reference symbols outside the time of their allocation of data symbols. For example, the second UE 107 was scheduled with a second allocation 32b of symbols 7, 8, 9, 11, 12, and 13 and was inserted into that second allocation 32b, i.e., at symbol 10. A reference signal 36 is transmitted. The second UE 107 may also transmit reference signals on other reference symbols outside its second allocation 32b. In this case, the further reference symbols are transmitted in the first allocation 32a, ie the first seven symbols of the subframe, eg symbol 3.

Thus, the first UE transmits data in the first allocation 32a, ie 6 data symbols in symbols 0, 1, 2, 4, 5 and 6. Furthermore, the first UE transmits a 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 within or adjacent to a different UE's data symbol allocation, eg, at symbol 10 . In this example, subframe 30a includes data allocations for multiple UEs, eg, a first UE and a second UE. Each UE may transmit reference signals in time intervals corresponding to having data allocations for entire subframes. As such, the reference signals for each UE are transmitted with conventional periodicity in subframes, even though the data allocation (and TTI) is only a portion of the subframe for each UE.

In this example, both the first UE and the second UE transmit reference signals 36 on the same symbols, ie on the same resource elements. As such, the first UE and the second UE share uplink physical resources. 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 of 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 reference signals to multiplex with reference signals from other UEs (eg, a second UE). In some examples, the reference signals are multiplexed by code multiplexing. For example, the first UE is configured to generate and transmit reference signals with cyclic shifting. Cyclic shifting provides multiplexing with other reference signals, eg, by orthogonalizing this reference signal with reference signals from other UEs using different cyclic shifts. In some examples, the reference signals are generated using orthogonal cover codes (OCC) to provide multiplexing.

Due to cyclic shift (and OCC), respective reference signals from multiple UEs are orthogonal to each other. In some examples, the reference signals from each of the UEs in the cell are based on the same base sequence (eg, derived from the cell ID). In some examples, multiplexed reference signals are transmitted in the same cell, ie to 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 to data symbols. A first UE allocation 32a is distinct from that of another (eg, second) UE allocation 32b. In this case, there is no time overlap between data symbols transmitted from separate UEs. A UE may use different time resources on the same subcarrier. In some aspects, only the same frequency resource is used by the first UE and the second UE, ie in the first allocation 32a and the second allocation 32b. As such, the first UE is not given a different frequency allocation of resources at the same time as the second UE.

A separate time physical resource allocation for data symbols is in contrast to multiplexed reference signals. A reference signal from a 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 a subframe with symbols numbered 0-13. In some examples, reference signals are transmitted on multiple subcarriers (frequency ranges) in one or more time allocations. Thus, the reference signals are multiplexed in a common time allocation (symbol) while the data symbols are separate in time allocation.

In this case, the first UE data symbol and the second UE data symbol are transmitted within a subframe time period and on the same frequency resource. Within that time period and on the same frequency resource, reference signals for both the first UE and the second UE are transmitted. The reference signals for both the first UE and the second UE are sent at the same time (ie, on the same symbols), eg, using code multiplexing.

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

In some aspects the signal is an uplink signal and/or utilizes SC-FDMA. In this example, 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 due to the reduced length of time in the TTI (ie, reduced number of symbols).

UEs are assigned separate data allocations of time/frequency resources that are not shared with another UE of the UEs. In particular, a separate data allocation is a time allocation of physical resources that is separate from one or more further UEs. In some examples, one or more additional UEs only use the same frequency resources. 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. The time allocation refers to the time at which transmission is scheduled (and therefore possible) for the UE, not how many data symbols the UE actually transmits in the time allocation. In some aspects, time allocation may refer to symbol periods, symbol time periods, or scheduling periods.

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

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

The first and second UEs with multiplexed reference signals and separate time allocations of data symbols are not frequency multiplexed, i.e. the first and second UEs share the same physical frequency resource. do. The same physical frequency resource may also be referred to as a resource block frequency range (eg, 12 subcarriers), a multiple resource block frequency range, or other radio frequency range. A UE's data symbols are transmitted on the same physical frequency resource as another UE's data symbols. In some aspects, the frequency range assigned to the data symbols for the first UE is the same as (or overlaps with) the frequency range assigned to the data symbols for the second UE. Multiplexed demodulation reference signals are transmitted by the first UE and the second UE in the same frequency range.

In FIG. 4, subframe 40 is constructed by transmissions from multiple UEs arranged as shown. In this example, the first data allocation 42a for 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 a subframe.

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

A subframe time length of 1 ms has two time units (symbols) for the reference signal, eg, a first reference symbol 36a at position symbol 3 and a second reference symbol 36b at position symbol 10 . In some examples, the first reference symbol 36a includes multiplexed reference symbols from all UEs with data allocations in that subframe or physical resource block pair. A second reference symbol 36b also contains multiplexed reference symbols from all UEs with 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 multiplexed references from all of the multiple UEs transmitting data in that physical resource block pair, e.g. Including signal. The reference signal may be sent by the UE at times when the data symbols are not consecutive, eg, the reference signal at symbol 10 for the first UE with data allocation 42a. At a particular time, data for only one UE is transmitted on physical resource blocks.

This allows the receiver to have high accuracy in subsequent time variations 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 entire length of the subframe.

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

In these examples, multiple UEs are scheduled with separate time allocations of data symbols in slots or physical resource blocks. A reference signal is transmitted by a separately scheduled UE in that slot or physical resource block. Such reference signals are multiplexed. The multiplexed reference signals may be reference signals 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 denote a physical resource block pair. Alternatively, a subframe to 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 a frequency range assigned to a set of time multiplexed UEs, as described above. In a frequency domain, only one UE is assigned or transmits a data symbol at a particular time.

Allocation of physical resources according to the present disclosure is based on physical time and frequency resources. Aspects relate to multiple UEs sharing in physical resource blocks or physical resource block pairs. Multiple UEs can transmit in a frequency range larger than one physical resource block or physical resource block pair (eg, 12 subcarriers). The frequency ranges or subframes mentioned do 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 range.

FIG. 5 shows a further example of physical resource allocation in subframe 50 . In this example, two symbols in data allocation (eg, SC-FDMA) are included in the same TTI. Thus, a 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 separate first to sixth UE in the cell.

As such, each data symbol has a specific or unique time allocation of physical resources. In some aspects, different time resources are assigned to each UE transmitting within 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 a serving cell of a base station (eg implemented as an 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, symbols with multiplexed reference signals are not necessarily placed next to 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 demodulation of user data can be positioned 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, eg, 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 can transmit reference signals 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 respectively all UEs scheduled in that subframe or some (partial) UEs scheduled in that subframe. ) only.

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

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

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

The first through fifth allocations 62a, 62b, 62c, 62d, 62e are transmitted in the first subframe 60a. The first allocation 62a starts, for example, at symbol 1 after the start of the subframe. The reference symbols are located at conventional positions within the subframe, ie symbols 3 and 10 . Subframes 60 are arranged such that none of the data allocations are split into two non-consecutive portions 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 assignment 62b follows the first reference symbol 36a.

In this example, one UE's data symbols can be split between a first subframe 60a and a subsequent second subframe 60b or physical resource block pair. In this example, the data symbols of the sixth allocation 62f are split between subframes 60a, 60b. Subframes 60a, 60b are sometimes referred to as subframe pairs or contiguous resource block pairs. Thus, separate physical resource allocations of data symbols are separate time allocations in subframe pairs of communications to different user equipments. A 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 signals are multiplexed as described in any of the examples above.

FIG. 7 shows a further example of mapping 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 per subframe or physical resource block pair. For example, a first data allocation 72a for a first UE has only one symbol in a subframe. In this example, the 12 UEs have separate time allocations for data on the subframe time period and the same physical frequency resource. The first UE also transmits one or more reference signal symbols 36 in the subframe. Reference signals for multiple UEs are multiplexed onto 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 on all reference signal symbols, or on only one reference signal symbol. As such, each reference signal symbol is a multiplex of all or part of the reference signals from UEs transmitting data in that subframe or physical resource block pair.

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

Up to 12 different UEs, for example, 3GPP TS 36.211, "Physical Channels and Modulation" Technical Specification, 3rd Generation Partnership Project, Specification Group Radio Access Network, Enhanced Universal Terrestrial Radio Access (E-UTRA), V12.5 .0. , http://www. 3 gpp. org/ftp/Specs/archive/36_series/ can be code multiplexed onto the same symbol by using cyclic shifts, for example as specified in the LTE Release 8 specification. A cyclic shift may be viewed as a linear phase rotation of the frequency domain of the reference signal.

A 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 a 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 additionally, 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, any example reference signal 36 can be multiplexed using a frequency comb. A reference signal may be considered to repeat at a predetermined frequency or subcarrier interval. For example, a "repetition factor" of 6 can be used such that the reference signal from the UE is transmitted on every 6th carrier. In some examples, for example, the LTE Release 8 cell-specific reference signal (CRS) design is used when appropriate for the radio channel coherence bandwidth. In some examples, frequency multiplexing occurs on the same frequency resources used by data allocations. Multiple frequency multiplexed demodulation reference signals are transmitted simultaneously, eg, on symbol 3 and/or symbol 10 in a subframe.

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

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

In some aspects, the reference signals are multiplexed using both code multiplexing (eg, cyclic shift/OCC) and frequency multiplexing (eg, using frequency combs). A UE is configured with one or more parameters such that 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 sent in the same basic time unit of a subframe. In this case, resource elements that share the assigned time base unit are used for multiple reference symbols. The multiplexed reference symbols are from UEs that are also transmitting data within a resource block or resource block pair. In some examples, a resource block or resource block pair corresponds to time-frequency physical resources, eg, 7 or 14 symbols in the time domain and 12 subcarriers in the frequency domain.

In some aspects, reference signals are transmitted on physical resources along with data symbols. As such, the reference signals are sent in the same resource blocks or subframes or time adjacent resource blocks or subframes as the data symbols sent from the UE. For example, the frequency bandwidth (ie subcarriers used) by the reference signal is the same as the data from the UE. In some aspects, reference signals are always transmitted along with or on physical resources associated with data symbols.

In the above example, the reference symbols are placed in the central symbols (eg, SC-FDMA symbols) of the slots or resource blocks. The reference symbol is therefore centered in time in the slot. Alternatively, the reference symbols may be inserted at different positions without changing the principles of this disclosure. The use of reference signals in the middle of slots allows a base station (e.g., eNodeB) to use reference symbols for mixed interference measurements of legacy Release 8 UEs and UEs operating according to the methods of the present disclosure. . Positioning the reference signal as the central symbol, as also used by legacy UEs, means that the reference symbol represents the worst case interference scenario.

When the length of a TTI is shortened (i.e., less than the length of a slot or subframe), the one or more reference signals transmitted in each TTI suffer from relatively increased overhead and corresponding 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. (1 data symbol and 1 reference symbol). Furthermore, for a single symbol TTI, the current uplink (SC-FDMA) structure cannot be used because the symbol can be used for either reference signal or data, but not both. Overhead is reduced or data rate is increased by multiplexing reference symbols over non-multiplexed data symbols. Multiplexing of reference signals from different UEs is assumed to allow the same number of reference symbols to be used by each UE even if the TTI or transmission length in a subframe in that data allocation is shortened. may 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 contiguous with their associated data symbols. The reference signal (DM-RS) is still transmitted by the UE and associated with the data, and according to examples of this disclosure, latency is reduced without changing reference signal transmission timing.

FIG. 8 shows a further example of a subframe 80 of this disclosure. As described above in FIG. 7, resource allocation causes the UE to transmit reference signals 36 and data symbols in subframes 80, where the reference signals (but not data symbols) are multiplexed. The data allocation for each UE in a subframe is one symbol period, eg, the first data allocation 82a has a length of one symbol (TTI). In this example, the reference symbols 36 assigned to the UE precede (ie, are 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 following the third data allocation 82c. In this example, 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 symbols 36a are used for reference signal transmission. It is also the closest reference symbol in time. Reference signals from UEs with data allocations for symbols 4-9 (UE 4 through UE 9) are multiplexed into a single reference signal 36a. Reference signals from UEs with data allocations for symbols 11 to 2 (UE 10 to UE 14) of subsequent subframes are multiplexed into a further single reference signal 36b. The data allocation and associated reference signals may be viewed as being located over a pair of subframes, two resource blocks, or two physical resource block pairs.

A channel estimate is always available for the way the reference symbols are sent before the data symbols. Hence, there is no additional latency before channel estimates are obtained.

This alternative can be used in any of the above examples of the UE using the reference symbol closest (in time) to the data symbol, regardless of whether the reference symbol precedes or follows the data symbol. Contrast with policy. In some examples, the UE may transmit reference signals in all reference signal symbol allocations such that channel estimates close to the user data are available. Also, the UE is prepared to receive and process possible reception of user data.

A reference signal can be sent on several symbols (eg, SC-FDM symbols) in a slot or subframe period. As the number of symbols used for reference signals increases, more users can be multiplexed at the cost of greater reference signal overhead.

The use of reference symbol assignments closest to the data results in high quality channel estimation, especially in fading channels. For low speed UEs, fading may not be limiting and transmitting reference symbols before data can be used effectively. 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. A UE may be configured to transmit reference signals before being (dynamically) configured to transmit data, eg, on PUSCH. In such cases, the reference signal can 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. This application example 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 examples described, 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 sufficiently rich 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 at a specific time in a subframe when using spatial multiplexing of users with MU-MIMO (e.g., SC-FDM symbol ). Here, spatially multiplexed users may use different cyclic shifts or frequency combs for different reference signals.

In the UL MU-MIMO embodiment, 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 Duplexing (FDD). Examples of the present disclosure may be used in a time division duplex communication network.

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

Examples are applicable to UEs communicating with the same base station. In this case, the UE multiplexing the reference signal is transmitting the reference signal and data symbols to the same base station (eg, eNB). In some examples, different base stations are used for uplink and downlink. In this example, the base station used for signaling the user equipment (on the downlink) is different from 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 for the second base station (compared to the first base station). good.

Examples of this disclosure may reduce data transport time and control signaling (e.g., by reducing the length of the TTI) and/or control signaling processing time (e.g., the time it takes for the UE to process a grant signal). Reducing the time taken) results in reduced packet latency.

FIG. 9 illustrates an example node configuration for a base station or eNB 401 that can implement some of the example embodiments described herein. Base station 401 can include radio circuitry 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 radio circuit or communication port 410 can be configured as any number of transmitting, receiving, and/or transmitting units or circuits. It should further be appreciated that the radio circuit or communication port 410 may be in the form of any input or output communication port known in the art. Radio circuitry or communication port 410 may include RF circuitry and baseband processing circuitry (not shown).

Base station 401 can also comprise a processing unit or circuitry 420 that can be configured to schedule for configuring UEs according to any example of this disclosure. Processing circuitry 420 may be any suitable type of computational unit, such as a microprocessor, digital signal processor (DSP), field programmable gate array (FPGA), application specific integrated circuit (ASIC), or any other form. may be a circuit of Base station 401 may further include a memory unit or circuit 430, which may be any suitable type of computer readable memory and may be of the volatile and/or non-volatile type. Memory 430 can be configured to store received, transmitted, and/or measured 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 shows an example node configuration for a UE or wireless terminal 505 that is capable of performing one or more of the described examples. Wireless terminal 505 may be user equipment, a machine-to-machine type device, or any other device capable of communicating with a communication network. Wireless terminal 505 can include radio circuitry 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 radio circuit or communication port 510 may be configured as any number of transmitting, receiving, and/or transmitting units or circuits. It should further be appreciated that the radio circuit or communication port 510 may be in the form of any input or output communication port known in the art. Radio circuitry or communication port 510 may include RF circuitry and baseband processing circuitry (not shown).

Wireless terminal 505 can also include a processing unit or circuitry 520 that can be configured to obtain downlink broadcast transmissions, eg, to receive signaling to make up any example of this disclosure. A processing circuit or unit can be configured to transmit data symbols and multiplexed reference signals, in accordance with any example. The processing circuitry is configured to transmit subframes including the reference signal and user data multiplexed in separate symbols via the communication circuitry. The device may be otherwise configured as described above.

Processing circuitry 520 may be any suitable type of computational unit, such as a microprocessor, digital signal processor (DSP), field programmable gate array (FPGA), application specific integrated circuit (ASIC), or any other form. may be a circuit of Wireless terminal 505 may further include a memory unit or circuit 530, which may be any suitable type of computer-readable memory and may be of the volatile and/or non-volatile type. Memory 530 can be configured to store received, transmitted and/or measured data, device parameters, communication priorities, and/or executable program instructions.

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

At 111, the UE determines multiplexing information for reference signals. The multiplexing information may be received in signaling from the network or 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) to 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 known signaling used for cyclic shift in MU-MIMO. In some aspects, a UE is configured to receive scheduling for transmission of data from a base station. The received scheduling is for 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 reference signals. A reference signal is transmitted on the determined time/frequency resource. The transmitted reference signals are 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 data symbols may occur before and/or after reference signals used to demodulate the data symbols. Data symbols are sent on scheduled time resources that are distinct from those scheduled for other UEs using the same frequency and the same receive antenna port.

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

At 121, the base station receives a first reference signal from a first UE. Concurrently, at 123, the base station receives multiplexed second reference signals from the second UE. The base station demultiplexes the first reference signal and the second reference signal, eg, by code demultiplexing and/or frequency demultiplexing.

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

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

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 demodulation can use channel estimates derived from reference signals.

In a further aspect, the base station transmits multiplexing information to the first UE and the second UE to yield multiplexed reference signals for the first UE and the second UE. The transmitted information results in multiplexed reference signals that are split by the base stations.

In a further aspect, a base station determines scheduling for UEs served by the base station. The base station determines scheduling according to any example, e.g. determine a separate time allocation in each subframe (or subframes) to The base station is configured to transmit corresponding scheduling information to the first UE and the second UE to schedule the first UE data and the second UE data and/or reference signal allocation. .

The present disclosure may, of course, be practiced otherwise than as 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.

Those skilled in the art will appreciate that embodiments herein generally include methods performed by communication devices in wireless communication networks. A method is for transmitting reference signals (eg, DM-RS) along with data (eg, user data) on PUSCH in an LTE network. The method includes, for example, generating and transmitting reference signals suitable for multiplexing that are orthogonal to reference signals from other UEs transmitting on the same symbol (i.e., on the same time and frequency physical resources). can include

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

A 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 can be configured to determine data symbol assignments and reference signal configurations and/or to transmit data symbols and reference signals. The device is configurable as described above. The computer program contains instructions that, when executed by at least one processor of the device, cause the device to perform any of the methods herein.

A carrier contains the computer program described above, and the carrier is one of an electronic signal, an optical signal, a radio signal, or a computer-readable storage medium.

A number of implementations can benefit from the reduced latency provided by the examples of this disclosure. For example, aspects can enhance the perceived quality of experience, examples of which include gaming, 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 in e.g. smart glass, or specific machine communications that require low latency.

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

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

Aspects of the present disclosure are applicable to downlink and/or inter-device transmission and also to 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 inter-device transmission can utilize the described single carrier.

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

Claims (20)

A method in a user equipment for transmitting reference signals in a communication network, comprising:
determining multiplexing information for the reference signal;
transmitting the reference signal using the multiplexing information in the same time allocation as another user equipment's reference signal;
transmitting data symbols associated with the reference signal in separate time allocations of physical resources and on the same physical frequency resources relative to time allocations of data symbols of the other user equipment;
The method, wherein the reference signal is located at a position different from symbol 3 and symbol 10 of the subframe. 2. The method of claim 1, wherein the separate physical resource allocations of data symbols are separate time allocations of subframes, slots, physical resource blocks, physical resource block pairs, or pairs of subframes of communication to different user equipments. described method. The user equipment transmits the reference signal and the data symbols in a period of a slot, subframe, or two subframes, and the reference signal is transmitted to another user equipment in the slot, subframe, or two subframes. , and wherein the user equipment transmits data symbols in separate time allocations of the period of a slot, subframe, or two subframes. 2. Determining multiplexing information for the reference signals comprises determining information for code multiplexing the reference signals with one or more reference signals from the another user equipment. 4. The method of any one of 3 to 4. 5. The method of claim 4 , comprising generating the reference signal with a cyclic shift determined to provide code multiplexing with the one or more reference signals from the other user equipment. 6. A method according to claim 4 or 5 , comprising generating the reference signal at frequency intervals to provide frequency multiplexing with the one or more reference signals from the other user equipment. 7. A method according to any one of claims 1 to 6, wherein said data symbols are transmitted within a transmission time interval (TTI) which is less than one subframe and/or less than 1 millisecond. 8. The method of claims 1 to 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. A method according to any one of paragraphs. The method according to any one of claims 1 to 8, wherein said reference signals and data symbols are transmitted on PUSCH and/or said data symbols are SC-FDMA symbols. A method according to any one of claims 1 to 9, wherein said user equipment is communicating as part of a multi-user Multiple In Multiple Out (MU-MIMO) communication with further user equipment. 11. A method according to any one of claims 1 to 10, wherein transmitted symbols of said user equipment and said another user equipment are scheduled to be received on the same antenna port. A method in a base station for communicating with 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 first data symbols from the first user equipment;
receiving second data symbols from the second user equipment;
the first and second 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 resources;
The method, wherein the first and second reference signals are located at positions different from symbol 3 and symbol 10 of the subframe. signaling to said first user equipment and said second user equipment respectively with multiplexing information for said first reference signal and said second reference signal; and/or said first user equipment and 13. The method of claim 12, further comprising signaling the second user equipment with information regarding separate time allocation of physical resources for data symbol transmission. 14. The method of claim 13, wherein the multiplexing information is code multiplexing information and/or frequency multiplexing information. the first and second reference signals and the first and second data symbols in a single slot, physical resource block, subframe, physical resource block pair, or 15. A method according to any one of claims 12 to 14, received in adjacent subframes or physical resource block pairs. A user equipment configured to transmit a reference signal in a communication network,
a processing circuit configured to determine multiplexing information for the reference signal;
radio circuitry configured to transmit the reference signal using the multiplexing information in the same time allocation as another user equipment's reference signal;
The radio circuitry is configured to transmit data symbols associated with the reference signals in separate time allocations of physical resources and on the same physical frequency resources relative to time allocations of data symbols of the other user equipment. configured,
The user equipment, wherein the reference signal is located at a different position than symbol 3 and symbol 10 of the subframe. 17. The user equipment of claim 16, wherein the user equipment is configured to code and/or frequency multiplex a reference signal with the reference signal of the other user equipment. A base station configured to communicate with user equipment in a communication network, comprising:
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 configured to receive first data symbols from the first user equipment and to receive second data symbols from the second user equipment;
the first and second data symbols from the first user equipment and the second user equipment are on separate time allocations of physical resources and on the same physical frequency resource;
The base station, wherein the first and second reference signals are located at positions different from symbol 3 and symbol 10 of the subframe. determining multiplexing information for the first reference signal and the second reference signal and/or determining physical resources for data symbol transmission by the first user equipment and the second user equipment; processing circuitry configured to determine separate time allocations, said radio circuitry relating to such multiplexing information and/or said separate time allocations for said first user equipment and said second user equipment. 19. A base station according to claim 18, configured to transmit information. A computer program, adapted to perform the method according to any one of claims 1 to 14 when running on a computer.

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