JP2023075098A - User equipment, base station, and method performed by user equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new solution for reference signal transmission and reception.

SOLUTION: User equipment of the present disclosure includes: means for receiving downlink control information from a base station; means for determining, based on the downlink control information, whether or not a cyclic shift field corresponds to one of a first reference signal sequence and a second reference signal sequence, depending on the value of the cyclic shift field; means for determining one to which the cyclic shift field corresponds, of the first reference signal sequence or the second reference signal sequence; and means for generating the one of the first reference signal sequence or the second reference signal sequence based on the downlink control information.

SELECTED DRAWING: Figure 5

COPYRIGHT: (C)2023,JPO&INPIT

Description

TECHNICAL FIELD Embodiments of the present disclosure relate generally to wireless communication technology, and more particularly to methods and devices for transmitting reference signals and methods and devices for receiving reference signals.

Multi-antenna technology can significantly increase the data rate and reliability of wireless communication systems. Performance is particularly improved if both the transmitter and receiver have multiple antennas, resulting in a multiple-input multiple-output (MIMO) communication channel. Such systems and/or related techniques are commonly referred to as MIMO.

The Long Term Evolution (LTE) standard is currently rolling out enhanced MIMO support. LTE core components support MIMO antenna deployment and MIMO related techniques. Currently, one-dimensional (horizontal) antenna arrays can provide flexible beam adaptation in the azimuth domain only through a horizontal precoding process, while a fixed down-tilt is applied in the vertical direction.

Recently, it has been found that full MIMO capability can be exploited by exploiting a two-dimensional (2D) antenna plane, allowing user-specific elevation beamforming and spatial multiplexing in the vertical domain. Furthermore, it was also proposed that the Uplink (UL) demodulation reference signal (DMRS) supports additional orthogonal ports for partial overlap.

Also, sparse RS can be used in the time domain because the channel variation in the time domain is gradual when a high center frequency is used. In other words, in future 5G communications, in order to reduce overhead, only one or a few symbols in the time domain are proposed for RS transmission, and Zadoff-Chu (ZC) sequences are proposed in the novel subframe structure. is proposed to be used. For illustration purposes, FIG. 1 shows one of the novel subframe structures in which there is only one symbol in one TTI for RS transmission. However, it will be appreciated that in other possible novel subframe structures the symbols may be placed in other positions and/or may comprise one or more UL/DL symbols. .

Thus, only one or a few symbols of DMRS can be used for both UL and Down Link (DL) in future 5G communications. In such cases, one should consider using more orthogonal ports in the partially overlapping BWs to support higher-order multi-user MIMO (MU-MIMO). .

Therefore, new DMRS designs, as well as new standards, have been developed in the art to adapt new subframe structures to new channel characteristic variations in the time domain and to support more users or more layers. Signal transmission and reception solutions are required.

In the present disclosure, new solutions for reference signal transmission and reception are provided to alleviate or at least mitigate some of the problems in the prior art.

According to a first aspect of the present disclosure, a method of transmitting a reference signal is provided. The method includes receiving a reference signal configuration indication, wherein the reference signal resource is divided into at least two reference signal groups, the reference signal configuration indication indicating a reference signal configuration including a reference signal group configuration. and transmitting the reference signals using reference signal sequences in the reference signal groups indicated by the reference signal group configuration, the reference signal sequences being transmitted in other layers in different reference signal groups. Or can be multiplexed with other users.

In a second aspect of the disclosure, a method of receiving a reference signal is provided. The method includes transmitting a reference signal configuration indication, wherein the reference signal resource is divided into at least two reference signal groups, the reference signal configuration indication indicating the reference signal configuration including the reference signal group configuration. and receiving the transmitted reference signal by using the reference signal sequences in the reference signal groups indicated by the reference signal group configuration, the reference signal sequences being in different reference signal groups can be multiplexed with other layers of or other users.

In a third aspect of the disclosure, an apparatus is provided for transmitting a reference signal. The apparatus includes an indication receiving module configured to receive a reference signal configuration indication, wherein the reference signal resource is divided into at least two reference signal groups, the reference signal configuration indication being the reference signal group configuration, and a signal transmission module configured to transmit the reference signal using a reference signal sequence in the reference signal group indicated by the reference signal group configuration; Sequences can be multiplexed with other layers or other users in different reference signal groups.

In a fourth aspect of the disclosure, an apparatus is provided for receiving a reference signal. The apparatus includes an indication transmission module configured to transmit a reference signal configuration indication, wherein the reference signal resource is divided into at least two reference signal groups, the reference signal configuration indication being the reference signal group a signal receiving module configured to receive a transmitted reference signal by using a reference signal sequence in a reference signal group indicated by the reference signal group configuration; and the reference signal sequences can be multiplexed with other layers or other users in different reference signal groups.

According to a fifth aspect of the present disclosure, there is provided a computer readable storage medium embodied with computer program code which, when executed, causes an apparatus to operate in a method according to any embodiment of the first aspect. configured to run.

According to a sixth aspect of the present disclosure, there is further provided a computer readable storage medium embodied with computer program code which, when executed, causes an apparatus to perform operations in a method according to any embodiment of the second aspect. is configured to run

According to a seventh aspect of the present disclosure there is provided a computer program product comprising a computer readable storage medium according to the fifth aspect.

According to an eighth aspect of the present disclosure there is provided a computer program product comprising a computer readable storage medium according to the sixth aspect.

With the embodiments of the present disclosure, a novel solution is provided for reference signal transmission and reception, in which reference signal resources are divided into at least two reference signal groups, reference signals for different layers or users are: It can be multiplexed into different reference signal groups. This allows more mu-users with uneven bandwidth allocation to support significant channel estimation loss and PAPR problems.

These and other features of the present disclosure will become apparent through the detailed description of the embodiments set forth in the embodiments with reference to the accompanying drawings. In the accompanying drawings, the same reference numbers represent the same or similar components.
FIG. 1 schematically shows one of the possible UL symbols in the newly proposed subframe structure with reduced UL symbols. FIG. 2 schematically shows DMRS patterns in existing communication systems. FIG. 3 schematically illustrates the assignment of cyclic shifts to n ⁽¹⁾ _DMRS values. FIG. 4 schematically illustrates the allocation of cyclic shift fields to n ⁽²⁾ _DMRS,λ and [w ^(λ) (0) w ^(λ) (1)] in the uplink related DCI format. FIG. 5 schematically shows a flow chart of a method for transmitting reference signals according to one embodiment of the present disclosure. FIG. 6A schematically illustrates example DMRS patterns in frequency division multiplexing (FDM) mode based on DMRS grouping according to one embodiment of the present disclosure. FIG. 6B schematically shows example DMRS patterns in FDM mode based on DMRS grouping according to one embodiment of the present disclosure. FIG. 7 schematically illustrates example DMRS patterns in time division multiplexing (TDM) mode based on DMRS grouping according to one embodiment of the present disclosure. FIG. 8A schematically shows examples of possible DMRS patterns based on DMRS grouping in a further 5G communication system, according to one embodiment of the present disclosure. FIG. 8B schematically shows examples of possible DMRS patterns based on DMRS grouping in a further 5G communication system, according to one embodiment of the present disclosure. FIG. 8C schematically shows examples of possible DMRS patterns based on DMRS grouping in a further 5G communication system, according to one embodiment of the present disclosure. FIG. 8D schematically shows examples of possible DMRS patterns based on DMRS grouping in a further 5G communication system, according to one embodiment of the present disclosure. FIG. 8E schematically shows examples of possible DMRS patterns based on DMRS grouping in a further 5G communication system, according to one embodiment of the present disclosure. FIG. 8F schematically shows examples of possible DMRS patterns based on DMRS grouping in a further 5G communication system, according to one embodiment of the present disclosure. FIG. 9 schematically illustrates an example indication technique for indicating DMRS group configurations, according to one embodiment of the present disclosure. FIG. 10 schematically illustrates another indication technique for indicating DMRS group configurations, according to another embodiment of the present disclosure. FIG. 11 schematically illustrates a further indication technique for indicating DMRS group configurations, according to another embodiment of the present disclosure. FIG. 12 schematically shows a DMRS configuration for four new user equipments according to one embodiment of the present disclosure. FIG. 13 schematically shows DMRS signals transmitted in REs for UEi and UEj, according to one embodiment of the present disclosure. FIG. 14 schematically shows DMRS configurations for a legacy user equipment and two new user equipments according to one embodiment of the present disclosure. FIG. 15 shows n ⁽²⁾ _DMRS,λ and [w ^(λ) (0) w ^(λ) (1)] of the cyclic shift field in the uplink related DCI format, according to one embodiment of the present disclosure. Schematically shows an example of assignment of . FIG. 16 schematically shows a diagram of an example of multiple transmission time interval (TTI) scheduling, in accordance with one embodiment of the present disclosure. FIG. 17 schematically shows a diagram of another example of multiple TTI scheduling, according to another embodiment of the disclosure. FIG. 18 schematically illustrates an example of DMRS transmission based on a stagger pattern, in accordance with one embodiment of the present disclosure. FIG. 19 schematically shows DMRS signals transmitted on four REs for one OCC group, according to another embodiment of the present disclosure. FIG. 20 schematically illustrates a flow chart of a method for receiving reference signals according to one embodiment of the present disclosure. FIG. 21 schematically shows a block diagram of an apparatus for transmitting reference signals, according to one embodiment of the present disclosure; FIG. 22 schematically illustrates a block diagram of an apparatus for receiving reference signals, according to one embodiment of the present disclosure; FIG. 23 illustrates an apparatus 2310 that can be embodied as or included within a UE in the wireless networks described herein and a base station that can be embodied as or within a base station. 2320 further shows a simplified block diagram of an apparatus 2320 that may be included in the .

Hereinafter, the solutions provided in the present disclosure will be described in detail through embodiments with reference to the accompanying drawings. It should be noted that these embodiments are provided only to enable those skilled in the art to better understand and practice the present disclosure, and are not intended to limit the scope of the present disclosure in any way.

In the accompanying figures, various embodiments of the present disclosure are illustrated in block diagrams, flowcharts, and other figures. Each block or blocks in the flowcharts may represent a module, program, or portion of code containing one or more executable instructions for performing a particular logical function, and is not required in this disclosure. Blocks without are indicated by dashed lines. Also, although the blocks are drawn in a particular sequence for performing method steps, in practice the blocks need not be performed in the exact sequence shown. For example, blocks may be performed in reverse sequence or concurrently, depending on the nature of their respective operations. It should be noted that each block in the block diagrams and/or flowcharts, and combinations thereof, can be implemented by dedicated hardware-based systems, or a combination of dedicated hardware and computer instructions, to perform the specified functions/operations. .

Generally, terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. A reference to "a/an/the/said 'element, device, component, means, step, etc.'", unless expressly stated otherwise, includes a plurality of such devices, components, means, units. shall be construed openly as any reference to an instance of at least one element, device, component, means, unit step, etc., without excluding steps, etc. Also, as used herein, the indefinite article "a/an" does not exclude a plurality of such steps, units, modules, devices, objects, and the like.

Additionally, in the context of this disclosure, User Equipment (UE) refers to terminals, mobile terminals (MT), subscriber stations (SS), portable subscriber stations (PSS). ), Mobile Station (MS), or Access Terminal (AT), where some or all of the functions of a UE, terminal, MT, SS, PSS, MS, or AT can be included. Further, in the context of this disclosure, the term "BS" may be used to refer to, for example, Node B (NodeB or NB), Evolved Node B (eNodeB or eNB), Radio Header (RH), Remote Radio Head (RRH) Head), relays, or low power nodes such as femto, pico, etc.

In the following, firstly, DMRS patterns and mapping in existing communication systems are described with reference to FIGS. 2 to 4 for better understanding of the present disclosure.

Reference is first made to FIG. 2 which shows in more detail the DMRS pattern in an existing communication system. In existing communication systems, the physical uplink sharing channel (PUSCH) is based on Zadoff-Chu sequences. As shown in FIG. 2, for UEi, signals R _i (n) and R′ _i (n) are DMRS sequences in the first and second slots, respectively, which have different cyclic shifts. can have Signals R _i (n) and R′ _i (n) can have the same root sequence if sequence group hopping is disabled. In addition, two users transmitting signals with unequal bandwidths in MU-MIMO (hereafter referred to as mu-users) can use different OCC sequences in the two slots, allowing multiple Mu-users can use different cyclic shifts in DMRS.

So far, the DMRS patterns and mappings used in existing communication systems have been described, for more details, please refer to the relevant content in, for example, 3GPP TS 36.211.

In addition, as mentioned above, to support higher order multi-user MIMO (MU-MIMO) when one or a few DMRS symbols are used for both UL and downlink (DL) Also, one should consider using more orthogonal ports for partially overlapping BWs. However, in existing communication systems, only two multi-users with unequal bandwidth allocation are supported, or much standard effort and too large a constraint on the length of the ZC sequence is required. , the problem of Peak to Average Power Ratio (PAPR) arises. Accordingly, novel RS patterns and novel RS transmission and reception solutions are provided in this disclosure, which are described in more detail with reference to FIGS.

FIG. 5 schematically shows a flow chart of a method for transmitting reference signals according to one embodiment of the present disclosure. As shown in FIG. 5, first at step 510, a reference signal configuration indication is received, wherein the reference signal resource is divided into at least two reference signal groups, the reference signal configuration indication is a reference signal Fig. 3 shows a reference signal configuration including group configuration;

In embodiments of the present disclosure, RS resources, i.e. basic sequences for RS, can be divided into M different groups, and M different groups support more users or more layers. It can be used in either frequency division mode or time division mode to do so. Examples are then given to explain it in more detail, in which the DMRS resources are divided into two groups, ie M=2, for ease of understanding. However, those skilled in the art can readily appreciate that the number of M is not limited to two, but can be any suitable number.

In FIG. 6A, DMRS resources are divided into two groups, DMRS group 0 and DMRS group 1, and the REs for carrying DMRS group 0 and the REs for carrying DMRS group 1 are staggered in the frequency domain. Thus, for one DMRS port/layer, the length of the DMRS sequence is half the length of the PUSCH or legacy DMRS sequences not transmitted by the DMRS grouping proposed here. Therefore, the number of resource blocks (RBs) allocated to new UEs using DMRS grouping is a multiple of M (ie, 2). For example, if M=2, the number of RBs is 2, 4, 6, and so on. Alternatively, this condition may only need to be met if the number of RBs is less than six.

FIG. 6B schematically illustrates an example DMRS pattern in frequency division multiplexing mode based on DMRS grouping according to one embodiment of the present disclosure. The difference between the DMRS pattern shown in FIG. 6A and the DMRS pattern shown in FIG. 6B is that the reference signal groups are hopped to different symbols. In other words, for the DMRS in slot 0 and the DMRS in slot 1, the REs for carrying DMRS group 0 and the REs for carrying DMRS group 1 are staggered in different ways in the frequency domain. In the DMRS symbols in slot 0, the REs for carrying DMRS group 0 and the REs for carrying DMRS group 1 are DMRS group 0, DMRS group 1, DMRS group 0, DMRS group 1 . . . are staggered in the order of On the other hand, in DMRS symbols in slot 1, the REs for carrying DMRS group 0 and the REs for carrying DMRS group 1 are DMRS group 1, DMRS group 0, DMRS group 1, DMRS group 0, . . . are staggered in the order of

FIG. 7 schematically illustrates further examples of DMRS patterns based on DMRS grouping in a further 5G communication system, according to one embodiment of the present disclosure. A novel DMRS pattern as shown in FIG. 7 is achieved based on DMRS grouping but in time division multiplexing mode. That is, in DMRS symbols in slot 0, all REs carry DMRS group 0, while in DMRS symbols in slot 1, all REs carry DMRS group 1.

As a matter of fact, in future 5G communication systems, the frame structure may have another form. In future 5G communication systems, the TTI length may be very short, so one slot may contain 2 or 4 consecutive DMRS symbols, as shown in FIGS. 8A to 8E. Additionally, M is not limited to 2, but may be 3 or more, as shown in FIG. 8F.

DMRS Configuration Indication (DCI) format information or Radio Resource Control (RRC) regarding whether legacy DMRS pattern or new DMRS pattern is used, or in other words whether DMRS group configuration is enabled or not. : radio resource control) can be notified by a signaling bit. DMRS group configurations for different UEs or different layers of UEs can be indicated by RS signal indications, which can be explicit or implicit RRC signaling or DCI format information. That is, the DMRS group configuration can be indicated by the new RRC signaling, or by the DCI format, which also indicates the cyclic shift configuration and orthogonal cover code configuration. As an example, the reference signal group configuration can be implied by the cyclic shift configuration. As another example, the reference signal group configuration can be explicitly indicated by bits in the reference signal configuration indication.

Additionally, the RRC signaling for DMRS group configuration can be signaling separate from the RRC signaling for indicating whether the new DMRS pattern is in effect, or alternatively, the new DMRS pattern. is valid and the DMRS group configuration can be indicated in the same RRC signaling. Additionally, the same or different bits in the DCI format information can be used to provide DMRS group indication and indication of whether new DMRS is valid.

In one embodiment of the present disclosure, only one reference group can be used by one UE. In such cases, the DMRS group configuration can be implicitly indicated by the cyclic shift configuration, ie, the cyclic shift field in the DCI format. For example, in FIG. 9, some of the indices in the DCI formatted CS feed are for the new DMRS patterns and the rest of the indices in the DCI formatted CS field are for the legacy DMRS patterns. In other words, in the table for the CS field in the DCI for new UEs, all indices are split into two parts, the first part is for indicating to the UE to use the legacy DMRS pattern. and the second part is to indicate to the UE to use the new DMRS pattern. In the second part, the index is further split into two parts, one for DMRS group 0 and one for DMRS group 1 (for M=2). For example, as shown in FIG. 9, if the index in the DCI format is 000, the UE should transmit DMRS using the new DMRS group 0 of the new DMRS pattern. On the other hand, if the index in the DCI format is 010, the UE should use the legacy DMRS pattern. In such cases, no RRC signaling or DCI information bits are required to indicate whether legacy or new patterns are used for new UEs.

FIG. 10 schematically illustrates an indication technique for indicating DMRS group configuration according to another embodiment of the present disclosure, in which the index in the CS field of the DCI format is M part (M=2) divided into As shown in FIG. 10, the index in the CS field of the DCI format is split into two parts, one for DMRS group 0 and another for DMRS group 1 . For example, indices 000, 001, 010, 111 are included in the first group, DMRS group 0, and indices 011, 100, 101, 110 are included in the second group, DMRS group 1. Alternatively, the cyclic shifts (ie the n ⁽¹⁾ _DMRS values shown in FIG. 3) can also be divided into M groups based on RRC signaling. As an example, indices 0, 1, 2, and 3 correspond to DMRS group 0, and the remaining indices correspond to DMRS group 1. In such cases, 1-bit RRC signaling or 1-bit DCI information may be used to indicate whether legacy or new patterns are used.

In other embodiments of the present disclosure, more than one reference signal group is allowed to be used by one user equipment. In that case, the DMRS sequences for different layers of one UE can be multiplexed into different DMRS groups and a new mapping table can be used, which can be used in RRC signaling or in DCI format. It can be signaled by 1 bit. An example of the new table is shown in FIG. 11, where Δ _TC indicates the DMRS group configuration, the value 0 indicates DMRS group 0 and the value 1 indicates DMRS group 1 . From FIG. 11 it is clear that the DMRS group structure is tied to the CS index and layer. In such case, four UEs with two layers each can be scheduled in the following manner, fields 000+001+010+011 are used and multiplexing is implemented by intra-UE CS, inter-UE OCC and FDM. be.

If different layers in one UE can be multiplexed into different DMRS groups, the two layers shall be supported by OCC or FDM, for example field 100 or 101 by FDM and field 110 or 111 by OCC. can be done. At the same time, it can support up to 8 layers in single user (SU) mode. In this case, since the UE needs to be configured with a layer number, the UE can be implicitly informed of DMRS, OCC and FDM. As an example, if the UE is configured with 8 layers and field 000, then the UE uses the predefined mappings for Layers 0-3 to Layer 4 for CS, OCC, and _ΔTC as shown in the table. For -7, it can be assumed that the CS and OCC are similar to layers 0-3 but (1-Δ _TC ) for the FDM configuration.

In a further embodiment, for SU-MIMO with 4 or more layers, the CS, OCC and DMRS group configurations can be implicitly signaled to the UE. In such cases, the aggregated reference signal configuration can be used to support more layers in DMRS transmission. Aggregated reference signal configurations refer to reference signal configurations aggregated from more than one configuration. For example, an aggregated reference configuration may be formed by aggregating the reference signal configuration indicated by the reference signal configuration indication and another reference signal configuration predefined to be used therewith. Another reference signal configuration may be a configuration obtained from a reference signal configuration indicated by a reference signal configuration indication but having a different reference signal group configuration. Alternatively, the another reference signal configuration may be a reference signal configuration in a cyclic field mapping table, the reference signal configuration being different from the reference signal configuration indicated by the reference signal configuration indication and the reference signal configuration Predefined for use with the reference signal configuration indicated by the signal configuration indication. For example, for layer number v, the first v/2 layer and the next v/2 layer may use the same CS/OCC, but for different DMRS group configurations. Therefore, in this embodiment, even if the reference signal indication only indicates one reference signal configuration, two or more CS/OCC/ Aggregate DMRS group configurations.

As an example, in the legacy table shown in Figure 4, the two indices (ie two configurations) of the CS field are configured such that one UE indicates SC and OCC configurations for eight layers. The relationship between the two indices is fixed or predefined and can be signaled to the UE using the legacy CS field of the DCI format. For example, for 8 layers, index 000 actually represents indices 000 and 001 indicating CS/OCC for the first 4 layers and next 4 layers respectively, and layers 0, 1, 2 , and 3 use CS: 0, 6, 3, and 9 and OCC: [1 1], [1 1] [1-1], [1-1], and layers 4, 5, 6, 7 uses CS: 6, 0, 9, and 3 and OCC: [1 −1], [1 −1], [1 1] [1 1]. Or, alternatively, index 000 can be used to indicate CS/OCC for even layers, e.g. Can be used to indicate CS/OCC for 5, 7.

Returning to FIG. 5, and as seen therein, at step 520, reference signals are then transmitted using the reference signal sequences in the reference signal groups shown in the reference signal group configuration, where the reference signal sequences are: It can be multiplexed with another layer or another user in a different reference signal group.

After receiving the reference signal configuration information, the UE may transmit DMRS sequences according to the configuration indicated in the reference signal configuration information.

Taking four 1-layer UEs as an example, UE0, UE1, UE2 and UE3 are configured with indices 000, 001, 100 and 101 respectively in DCI format. FIG. 12 shows the CS configuration, OCC configuration, and DMRS signals transmitted in slot 0 or slot 1 when four new UEs are paired. In the current standard, when sequence group hopping is disabled, the cyclic shift offset between R'i and Ri should be the same for all those UEs to support MU-MIMO. That is, R'i(n) should be equal to e ^jan Ri(n). In other words, the cyclic shift index offset (or after modulo by 12) between two slots is the same for all mu-users. For example, for UE0, the cyclic shift indices for slots 0 and 1 are 0 and 6, respectively, and the index offset value is 6. For UE3, the indices of the two slots are 8 and 2, respectively, and the offset after modulo 12 is 6.

FIG. 13 shows reference signals transmitted in two slots using the new DMRS format by two UEs, where the four nearest REs, namely the first two REs in slot 0 and slot 1, are shown. One reference signal is further shown below for clarity of illustration. The symbols in the four closest REs are given by
[ R ₀ (n) e ^jan R ₀ (n) 0 0 ]
[ R ₁ (n) -e ^jan R ₁ (n) 0 0 ]
[ 0 0 R ₂ (n) e ^jan R ₂ (n)]
[ 0 0 R ₃ (n) -e ^jan R ₃ (n)]

From the above equation, it can be seen that for the two new UEs, orthogonality is achieved among these four REs even though they have unequal bandwidths.

However, when legacy UEs are paired with new UEs, orthogonality cannot be achieved because they use different DMRS patterns and legacy UEs are not multiplexed into different DMRS groups. In other words, for the same frequency resource, the length of the legacy DMRS sequence is twice the length of the new DMRS sequence. Therefore, basically, the resource index of the legacy DMRS sequence is twice that of the new DMRS sequence when the starting frequency positions of the legacy UE and the new UE are the same. FIG. 14 shows an example of CS configuration, OCC configuration, and DMRS signals transmitted in slot 0 and slot 1 when a legacy UE is paired with a new UE. The four closest REs are given by the following equations.
[ R ₀ (2n) e ^ja2n R ₀ (2n) R ₀ (2n+1) e ^ja(2n+1) R ₀ (2n+1) ]
[ R ₁ (n) -e ^jan R ₁ (n) 0 0 ]
[ 0 0 R ₂ (n) -e ^jan R ₂ (n) ]

From the above equation it is clear that orthogonality cannot be achieved. In fact, to achieve orthogonality, the cyclic shift offset between two slots for new UEs should be twice the cyclic shift offset for legacy UEs. In other words, except for the OCC sequence, the phase shift of the two slots should be kept the same as the legacy in the same frequency resource n, ie R' ₁ /R ₁ =R' ₀ /R ₀ . Therefore, in such cases, it is required to increase the inter-slot cyclic shift offsets for the new user equipments transmitting the reference signals in order to improve the orthogonality between the new user equipments and the legacy user equipments. be done.

ＤＭＲＳグループ１に対しては、基準信号シーケンスは、下記のように変更できる。

ここで、Ｍ^RS _SCは、ＤＭＲＳシーケンス長である。従って、レガシーＵＥ_０と新規ＵＥ_１とに同じ周波数リソースが割り当てられた場合、ＵＥ_１のＤＭＲＳシーケンス長は、ＵＥ_０のＤＭＲＳシーケンス長の半分である。 In one embodiment of the present disclosure, the cyclic shift is magnified by M when the DMRS sequence is generated. For example, for DMRS group 0, the reference signal sequence is modified as follows.

For DMRS group 1, the reference signal sequence can be modified as follows.

where M ^RS _SC is the DMRS sequence length. Therefore, if legacy UE ₀ and new UE ₁ are assigned the same frequency resource, UE ₁ 's DMRS sequence length is half of UE ₀ 's DMRS sequence length.

After the DMRS sequence is changed as suggested, the new symbols in the nearest four REs are given by
[ R ₀ (2n) e ^ja2n R ₀ (2n) R ₀ (2n+1) e ^ja(2n+1) R0 (2n+1) ]
[ R ₁ (n) -e ^ja2n R1 (n) 0 0 ]
[ 0 0 R ₂ (n) -e ^ja(2n+1) R2 (n) ]

It can be seen from the above equation that orthogonality is obtained between legacy and new UEs.

However, it can be seen that the orthogonality between different CSs is broken in the new DMRS sequences. For example, the orthogonality between CS0 and CS6 is broken. In the existing DMRS configuration, the cyclic shift offset is 6, and the two closest REs in the frequency domain can be one orthogonal group in the legacy pattern. That is, in the frequency domain, it can be transformed into an orthogonal frequency code over a block of two consecutive subcarriers. As a result, the granularity of channel estimation is (approximately) one per two subcarriers. This is not guaranteed after the cyclic shift offset is increased when the DMRS sequence is generated.

従って、新規なＤＭＲＳパターンにおいて、ＣＳオフセット６に代えてＣＳオフセット３が使用されるべきである。そのような場合、新規ユーザ機器に対する巡回シフトは、異なる巡回シフト間の直交性を保つために減少できる。そのような場合、ｎ⁽¹⁾ _DMRS及び／又はｎ⁽²⁾ _DMRS,λを縮小できると考えられる。つまり、ｎ_cs,λの等式は、下記のように変更されることができる。

別のオプションとして、新たな巡回シフト値が導入されることができる。特に最大で２つのレイヤに対し、第１レイヤと第２レイヤとの間のＣＳオフセットは３であるべきである。例えば、３ＧＰＰ ＴＳ ３６．２１２の表５．５．２．１．１－１においてインデックス０００に対応する関連する値０，６を、０，３に修正できる。図１５は、本開示の実施形態に従う、上りリンクに関連するＤＣＩフォーマットにおける巡回シフトフィールドのｎ⁽²⁾ _DMRS,λ、及び［ｗ^(λ)(0) ｗ^(λ)(1)］への割当ての例を模式的に示す。そのような場合、ｎ_cs,λの古い等式、又は下記に示されるように６による剰余が使用され得る。

In embodiments with increased cyclic shift offsets, the orthogonality of CS offset 3 results in orthogonal frequency codes across blocks of two consecutive DMRS subcarriers. In addition, two CSs with 6 offsets yield the same DMRS sequence.

Therefore, CS offset 3 should be used instead of CS offset 6 in the new DMRS pattern. In such cases, the cyclic shifts for the new user equipment can be reduced to preserve orthogonality between different cyclic shifts. In such cases, it is conceivable that n ⁽¹⁾ _DMRS and/or n ⁽²⁾ _DMRS,λ can be reduced. That is, the equation for n _cs,λ can be changed as follows.

As another option, new cyclic shift values can be introduced. Specifically, for a maximum of two layers, the CS offset between the first and second layers should be 3. For example, the associated values 0,6 corresponding to index 000 in Table 5.5.2.1.1-1 of 3GPP TS 36.212 can be modified to 0,3. FIG. 15 shows n ⁽²⁾ _DMRS,λ and [w ^(λ) (0) w ^(λ) (1)] of the cyclic shift field in the uplink related DCI format according to an embodiment of the present disclosure. Schematically illustrates an example of allocation. In such cases, the old equation for n _cs,λ , or modulo by 6 as shown below can be used.

As an example, 1-bit DCI information or RRC signaling may be used to indicate whether new DMRS patterns/sequences or legacy DMRS patterns/sequences are used. For the new one, the CS offset between the second layer and the first layer is 3. Since the CS offset is scaled by a factor M, the associated DMRS sequences derived from indices 000 and 001 are the same, the associated DMRS sequences derived from indices 010 and 111 are the same, and the associated DMRS sequences derived from indices 011 and 110 are the same. The associated DMRS sequences derived are the same, and the associated DMRS sequences derived from indices 100 and 101 are the same. Therefore, all CS indices can be divided into two groups, one group corresponding to one DMRS group and having different associated DMRS sequences. For example, indices 000, 010, 011, 100, 101 may correspond to DMRS group 0, and the remaining indices may correspond to DMRS group 1. That way, when the UE receives the index 000, it means that the UE belongs to DMRS group 0.

In addition, considering backward compatibility, the phase shift between two slots of one subframe for new UEs should be kept the same as the legacy one.

一方、ＤＭＲＳグループ１に対しては、下記式となる。

For DMRS group 0, the reference signal sequence can be kept as is in the legacy formula below.

On the other hand, for DMRS group 1, the following formula is obtained.

Therefore, in this solution, the cyclic shift offset between two slots of one subframe for new UEs is kept M times that of the legacy one.

In addition, it can be seen that in further 5G communication systems the TTI is very short. In scenarios with very short TTI lengths, DMRS can be removed in some TTIs. In other words, DMRS is not transmitted in every TTI. In this case, one or a few bits in the physical control signaling can be used to inform the UE how many DMRS symbols are used or if there are any DMRS symbols in the current TTI. If there is no DMRS in the TTI, the UE can demodulate the data using the previous DMRS. In addition, retransmissions without DMRS can be implemented by using DMRS in previous transmissions or initial transmissions.

Additionally, multiple TTI scheduling may be considered. In other words, the eNB only configures the control signaling information in one TTI and the UE can receive and/or transmit data in multiple TTIs based on the control signaling information. Therefore, in such cases, one or a few TTIs may contain DMRS. As another option, an OCC sequence of length L can be used, which is shown in FIG. As shown, OCC or DFT sequences of length L can be applied in the DMRS for those L TTIs. In this case there is only one DMRS in each TTI. Taking L=4 as an example, four orthogonal OCC sequences can be multiplexed into the DMRS sequence. Thus, up to 4 layers or 4 mu-users can be multiplexed with an OCC sequence.

As a further option, 6 DFT sequences can also be used, as shown in FIG. In such cases, two DMRS sequences may be sent in each TTI, and the DFT sequence values may be multiplexed with the DMRS sequences in each TTI. Thus, up to 6 layers or users can be multiplexed with 6 DFT sequences.

In another different embodiment, each user or layer can be transmitted by using M DMRS groups in a staggered pattern. Stated another way, one UE transmits multiplexed DMRS sequences based on a staggered pattern with M DMRS groups. In this embodiment, the UE needs to transmit DMRS sequences in each DMRS group for all layers. In such cases, different UEs can be multiplexed with different OCC sequences.

For example, if only one symbol is used for DMRS transmission, as shown in FIG. 18, both UE ₀ and UE ₁ transmit reference signal sequences in a staggered pattern using M DMRS groups. and the two UEs transmit reference signals in MU-MIMO mode with OCC=2 in the same symbol, where [W ₀₀ W ₀₁ ]=[1 1] and [W ₁₀ W ₁₁ ]=[1 −1]. In such a case, UE ₀ with one layer transmits DMRS sequence W ₀₀ ×R ₀ in DMRS group 0 and DMRS sequence W ₀₁ ×R′ ₀ in DMRS group 1, while in the same symbol , UE ₁ transmits the DMRS sequence W ₁₀ ×R ₁ in DMRS group 0 and the DMRS sequence W ₁₁ ×R′ ₁ in DMRS group 1 . In another case where two symbols are used for DMRS transmission, eg, in an R10 uplink DMRS pattern, as shown in FIG. 19, for UEi, different CS, R ⁰ i, R ¹ i, R Four ZC sequences with ² i, R ³ i can be used, thus extending the R10 uplink MU-MIMO mechanism with OCC=4 to support four MU users. , and UEs can be scheduled on different bandwidths. In such cases, the OCC may be:
[w _i0 w _i1 w _i2 w _i3 ] = [1 1 1 1], or
[1 -1 1 -1], or
[1 1 -1 -1], or
[1 -1 -1 1]

It should be noted that in embodiments where each user or layer can be transmitted in a staggered pattern using M DMRS groups, the DMRS sequences can be divided between new and legacy UEs and different CSs, as described above. can be modified backwards compatible to preserve orthogonality between In other words, the cyclic shift offset between the four ZC sequences should be kept the same for all UEs. In particular, _for UEi, the cyclic shift offset between ^R1i _and ^R2i is the same as the offset between _{R1j and} ^R2j for UEj scheduled with UEi in one TTI ^. can be. On the other hand, if the new UE is multiplexed with the legacy UE, the cyclic shift offset between the DMRS sequences of the two slots should also be the same as the legacy one.

Additionally, additional schemes can be used to improve transmission performance. For example, when DMRS groups are enabled, the power in one DMRS RE is double that in the PUSCH if the power of the DMRS symbols and the power of the PUSCH symbols are kept the same within one TTI. . Furthermore, if the power of one DMRS RE and the power of one PUSCH are kept the same, the power of DMRS symbols will be half of the power of PUSCH symbols. These represent power imbalances between different symbols. Therefore, the scaling factor can be changed to avoid power imbalance.

Therefore, in section 5.5.2.1.2 of 3GPP TS 36.213, the amplitude scale factor can be changed as delta×β _PUSCH , where delta is 1 or √2 and the default information can be notified to the UE as As an example, for a UE with a novel DMRS pattern, the amplitude scale factor is delta×β _PUSCH . Alternatively, the eNB may signal the delta value to the UE using RRC signaling, and the eNB may select one value from multiple values for the UE. For example, candidate values for delta can be {1, √2}, or {1, √2, √0.5, etc.}. In that way, power imbalance can be greatly mitigated.

So far, the description has been mainly for reference signal transmission solutions. Also provided in this disclosure is a method of receiving a reference signal as described with reference to FIG.

As shown in Figure 20, method 2000 may start at step 2010, where a reference signal configuration indication is transmitted. In particular, as described above, the reference signal resource is divided into at least two reference signal groups, and the reference signal configuration indication can indicate the reference signal configuration including the reference signal group configuration.

In one embodiment of the present disclosure, the reference signal resource is divided into at least two reference signal groups, the at least two reference signal groups are multiplexed in either frequency division multiplexing mode or time division multiplexing mode, such so that more users or more layers can be supported with limited antenna port resources. Additionally, in frequency division multiplexing mode, the at least two reference signal groups can also be hopped on different symbols.

In other embodiments of the present disclosure, the reference signal configuration indication may further indicate a cyclic shift configuration and an orthogonal cover code configuration in addition to the reference signal group configuration. This means that with the same reference signal indication, ie DCI format, cyclic shift configuration, quadrature or barcode configuration and reference signal group configuration can be indicated. For example, the reference signal group configuration may be implicitly indicated by the cyclic shift configuration, or alternatively may be explicitly indicated by bits of the reference signal configuration indication. In addition, whether the reference signal group configuration is valid can be indicated by a bit in the reference signal configuration indication or by using separate RRC signaling.

In some embodiments of the present disclosure, only one reference signal group is allowed to be used by one user equipment. In such case, a portion of the indices for the cyclic shift configuration is reserved for legacy reference signal patterns, the remaining portion of the indices is divided into at least two groups, each of the divided indices having at least two assigned to a corresponding one of one reference signal group. Alternatively, the indices for the cyclic shift configuration can be divided into at least two groups, each of the divided indices being assigned to a corresponding one of the at least two reference signal groups.

In some embodiments of the present disclosure, more than one reference signal group is allowed to be used by one user equipment. In such cases, the reference signal group indication can be tied to the index for the cyclic shift. In other words, for a particular index for cyclic shift, the reference signal group indication is predefined.

Then, as shown in step 2020 of FIG. 20, the reference signals are received and transmitted by using the reference signal sequences in the reference signal groups indicated by the reference signal group configuration, where the reference signals The sequences can be multiplexed with another layer or another user in a different reference signal group.

After the reference signal configuration indication is sent to the UE, the UE transmits reference signals using the reference signal sequences in the reference signal group indicated by the reference signal group configuration. The eNB may receive reference signals from the UE, and the reference signal sequences may be multiplexed with different layers or different users in different reference signal groups.

Additionally, reference signals can also be transmitted using an aggregated reference signal configuration to support more layers. The aggregated reference signal configuration may be a reference signal configuration aggregated from more than one configuration, the aggregated reference signal configuration being the reference signal configuration indicated by the reference signal configuration indication and the reference signal configuration may be formed by aggregating different reference signal configurations predefined to be used with. The alternate reference signal configuration, indicated by the reference signal configuration indication configuration, may be a reference signal configuration obtained from a reference signal configuration with a different reference signal group configuration, or indicated by the reference signal configuration indication. There may be different reference signal configurations in a cyclic field mapping table, predefined for use with the reference signal configurations.

The eNB demodulates the reference signal according to the reference signal configuration sent to the UE and learns the channel conditions.

In embodiments of the present disclosure, a new solution for transmitting and receiving reference signals is provided, in which the reference signal resources are divided into at least two reference signal groups, and reference signals for different layers or users are provided. Signals can be multiplexed into different reference signal groups. Therefore, more mu-users with unequal bandwidth can be supported without significant channel estimation loss and PAPR loss.

Additionally, FIG. 21 schematically illustrates a block diagram of an apparatus for transmitting reference signals, according to one embodiment of the present disclosure.

As shown in FIG. 21, the device 2100 has an indication reception module 2110 and a signal transmission module 2120 . The indication receiving module 2110 may be configured to receive a reference signal configuration indication, wherein the reference signal resource is divided into at least two reference signal groups, the reference signal configuration indication is the reference signal group 1 shows a reference signal configuration including configuration; The signal transmission module may be configured to transmit the reference signals using reference signal sequences in the reference signal groups indicated by the reference signal group configuration, the reference signal sequences being different layers of different reference signal groups or Can be multiplexed with another user.

In one embodiment of the present disclosure, at least two reference signal groups can be multiplexed in either frequency division multiplexing mode or time division multiplexing mode. In frequency division multiplexing mode, at least two reference signal groups can also be hopped to different symbols.

In another embodiment of the present disclosure, the reference signal configuration may further indicate a cyclic shift configuration and an orthogonal cover code configuration. In this case, the reference signal group configuration can be implicitly indicated by the cyclic shift configuration, or can be indicated explicitly by bits of the reference signal configuration indication. Additionally, whether the reference signal group configuration is valid can be indicated by separate RRC signaling, but can also be indicated by a bit of the reference signal configuration indication.

In further embodiments of the present disclosure, only one reference signal group may be authorized for use by a user. In such cases, a portion of the index of the cyclic shift configuration can be reserved for the legacy reference signal pattern, and the remaining portion of the index is divided into at least two groups, each group comprising at least two reference signal patterns. assigned to a corresponding one of the signal groups. Alternatively, the indices for the cyclic shift configuration can be divided into at least two groups, each group assigned to a corresponding one of the at least two reference signal part loops.

In further embodiments of the present disclosure, more than one reference signal group can be used by the user.

In further embodiments of the present disclosure, the reference signals may be transmitted using an aggregated reference signal configuration to support more layers, the aggregated reference signal configuration being a reference signal configuration indicator. It is formed by aggregating the reference signal configuration indicated by the application and another reference configuration predefined to be used with that reference configuration. In this case, the alternate reference signal configuration may be the reference signal configuration indicated by the reference signal configuration indication but obtained from the reference signal configuration of a different reference signal group configuration. Alternatively, the another reference signal configuration may be a different reference signal configuration in a cyclic field mapping table predefined for use with the reference signal configuration indicated by the reference signal configuration indication.

Additionally, to improve orthogonality between new user equipments and legacy user equipments, the apparatus 2100 is configured to increase the cyclic shift offset between slots for new user equipments transmitting reference signals. may further comprise an offset increment module 2130 . Additionally, in order to preserve orthogonality between different cyclic shifts, apparatus 2100 includes a shift reduction configured to reduce the cyclic shifts for new user equipments in order to preserve orthogonality between different cyclic shifts. A module 2140 may also be included.

FIG. 22 further illustrates an apparatus for receiving reference signals, according to one embodiment of the present disclosure. As shown in FIG. 22, device 2200 may have an indication transmission module 2210 and a signal reception module 2220 . The indication transmission module 2210 may be configured to transmit a reference signal configuration indication, wherein the reference signal resource is divided into at least two reference signal groups, the reference signal configuration indication comprising: Figure 3 shows a reference signal configuration including group configuration; Signal receiving module 2220 may be configured to receive reference signals transmitted using reference signal sequences in a reference signal group indicated by the reference signal group configuration, where the reference signal sequences are of different reference signal groups. It can be multiplexed with another layer or another user.

In one embodiment of the present disclosure, at least two reference signal groups can be multiplexed in either frequency division multiplexing mode or time division multiplexing mode. In frequency division multiplexing mode, at least two reference signal groups can also be hopped to different symbols.

In another embodiment of the present disclosure, the reference signal configuration may further indicate a cyclic shift configuration and an orthogonal cover code configuration. In this case, the reference signal group configuration can be implicitly indicated by the cyclic shift configuration, or can be indicated explicitly by bits of the reference signal configuration indication. Additionally, whether the reference signal group configuration is valid can be indicated by separate RRC signaling, but can also be indicated by a bit of the reference signal configuration indication.

In further embodiments of the present disclosure, only one reference signal group may be authorized for use by a user. In such cases, a portion of the index of the cyclic shift configuration can be reserved for the legacy reference signal pattern, and the remaining portion of the index is divided into at least two groups, each group comprising at least two reference signal patterns. assigned to a corresponding one of the signal groups. Alternatively, the indices for the cyclic shift configuration can be divided into at least two groups, each group assigned to a corresponding one of the at least two reference signal part loops.

In further embodiments of the present disclosure, more than one reference signal group can be used by the user.

In further embodiments of the present disclosure, the reference signals may be transmitted using an aggregated reference signal configuration to support more layers, the aggregated reference signal configuration being a reference signal configuration indicator. It is formed by aggregating the reference signal configuration indicated by the application and another reference configuration predefined to be used with that reference configuration. In this case, the alternate reference signal configuration may be the reference signal configuration indicated by the reference signal configuration indication but obtained from the reference signal configuration of a different reference signal group configuration. Alternatively, the another reference signal configuration may be a different reference signal configuration in a cyclic field mapping table predefined for use with the reference signal configuration indicated by the reference signal configuration indication.

So far, devices 2100 and 2200 have been briefly described with reference to FIGS. It should be noted that devices 2100 and 2200 may be configured to implement functionality similar to that described with reference to Figures 5-20. Therefore, for details on the operation of the modules in these devices, reference may be made to the description made with reference to FIGS. 5 to 20 for the respective steps of the method.

Additionally, components of devices 2100 and 2200 may be embodied in hardware, software, firmware, and/or any combination thereof. For example, the components of apparatuses 2100 and 2200 may each be implemented by a circuit, processor, or any other suitable selection device. Those skilled in the art will appreciate that the foregoing examples are for illustration only and not for limitation. For example, the number M of DMRS groups is not limited to two, even though taken as an example to explain this disclosure. Additionally, the reference signal reception and transmission solution is not limited to UL transmission only, but can also be used in DL transmission. However, in such a case, unlike the operation described above, instead of transmitting the reference signal configuration indication and receiving the reference signal, the eNB transmits both the reference signal configuration indication and the reference signal. do. On the other hand, instead of receiving the RS configuration indication and transmitting the reference signal, the UE receives the RS configuration indication and the reference signal and receives the reference signal based on the RS configuration indicated in the RS configuration indication. to demodulate.

Additionally, in some embodiments of the present disclosure, devices 2100 and 2200 may each have at least one processor. The at least one processor suitable for use with embodiments of the present disclosure may include, by way of example, both general and special purpose processors now known or developed in the future. Devices 2100 and 2200 may each have at least one memory. The at least one memory may include, for example, semiconductor memory devices such as RAM, ROM, EPROM, EEPROM and flash memory devices. At least one memory may be used to store a program of computer-executable instructions. Programs may be written in any high-level and/or low-level compilable or interpretable programming language. According to an embodiment, the computer-executable instructions may be configured to cause the apparatuses 2100 and 2200, in conjunction with at least one processor, to at least perform operations according to methods as discussed with reference to FIGS. 5-20, respectively.

FIG. 23 shows a device 2310 that may be embodied or included in a terminal device such as a UE for a wireless network in a wireless network and a base station such as a NB or eNB described herein. Also shown is a simplified block diagram of an apparatus 2320 that may be embodied in or included within a base station.

Device 2310 has at least one processor 2311 , such as a data processor (DP), and at least one memory (MEM) 2312 coupled to processor 2311 . Device 2310 may further have a transceiver (TX/RX) 2313 coupled to processor 2311 , which may be operable to communicatively connect to device 2320 . MEM 2312 stores program (PROG) 2314 . PROG 2314 may include instructions that, when executed on an associated processor 2311, enable apparatus 2310 to operate, eg, perform method 500, in accordance with embodiments of the present disclosure. The combination of at least one processor 2311 and at least one MEM 2312 may form processing means 2315 suitable for implementing various embodiments of the present disclosure.

The device 2320 has at least one processor 2321 such as a DP and at least one MEM 2322 coupled to the processor 2321 . Device 2320 may further have a suitable TX/RX 2323 coupled to processor 2321 , which may be operable for wireless communication with device 2310 . MEM 2322 stores PROG 2324 . PROG 2324 may include instructions that, when executed on an associated processor 2321, enable apparatus 2320 to operate, eg, perform method 2000, in accordance with embodiments of the present disclosure. The combination of at least one processor 2321 and at least one MEM 2322 may form processing means 2325 suitable for implementing various embodiments of the present disclosure.

Various embodiments of the present disclosure may be implemented by programs, software, firmware, hardware, or combinations thereof executed by one or more processors 2311, 2321.

MEMs 2312 and 2322 may be of any type suitable for the local technological environment, including, but not limited to, semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed It may be implemented using any suitable data storage technology such as memory and removable memory.

Processors 2311 and 2321 may be of any type suitable for the local technical environment, non-limiting examples include general purpose computers, special purpose computers, microprocessors, digital signal processors DPS, and multi-core processors. It may include one or more processors based on the processor architecture.

Additionally, the present disclosure may also provide a carrier containing the computer program described above, the carrier being one of an electrical signal, an optical signal, a radio signal, or a computer-readable medium. The computer readable medium can be, for example, random access memory (RAM), read only memory (ROM), flash memory, magnetic tape, optical compact discs such as CD-ROMs, DVDs, and Blue-ray discs, or electronic memory devices. obtain.

The techniques described herein can be implemented by various means, and an apparatus that performs one or more functions of the corresponding apparatus described in one embodiment can be implemented not only by means of the prior art, but also by one It also has means for implementing one or more functions of the corresponding apparatus described in the embodiment, which may be configured as individual means for separate functions or to perform two or more functions. have the means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. With firmware or software, implementation can be through modules (eg, procedures, functions, and so on) that perform the functions described herein.

Embodiments herein have been described above with reference to block diagrams and flowchart illustrations of methods and apparatus. It will be understood that each block of the block diagrams and flowchart illustrations, and combinations of blocks in the block diagrams and flowchart illustrations, respectively, can be implemented by various means including computer program instructions. These computer program instructions may be implemented by a general purpose computer, a specific use computer, or a computer program such that the instructions running on a computer or other programmable data processing apparatus produce the means for performing the functions identified in the flowchart blocks. It can be loaded onto other programmable data processing devices to create machines.

Although this specification contains many specific implementation details, these should not be construed as limitations on the scope of implementation or what may be claimed, rather than specific implementation details of particular implementations. It should be construed as a description of features that may be unique to the embodiments. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Further, features are described above as working in particular combinations, and even if originally claimed as such, one or more features from the claimed combination may in some cases be cut from the combination. and claimed combinations may be directed to subcombinations or variations of subcombinations.

It will be apparent to those skilled in the art that as technology advances, the inventive concept can be implemented in various ways. The above-described embodiments are provided to illustrate rather than limit the disclosure, and modifications and variations are possible without departing from the spirit and scope of the disclosure, as those skilled in the art will readily appreciate. It will be understood that there is Such modifications and variations are considered to fall within the scope of the disclosure and appended claims. The protection scope of the disclosure is defined by the appended claims.

Claims (18)

User equipment (UE: User Equipment),
means for receiving downlink control information from a base station;
means for determining, based on the downlink control information, that a cyclic shift field corresponds to either a first reference signal sequence or a second reference signal sequence, depending on the value of the cyclic shift field; with
The first reference signal sequence is a base sequence

by the cyclic shift α of

is defined by
The second reference signal sequence is a base sequence

by the cyclic shift α of

is defined by
The user equipment may further:
means for determining the one of said first reference signal sequence or said second reference signal sequence to which said cyclic shift field corresponds;
means for generating said one of said first reference signal sequence or said second reference signal sequence based on said downlink control information;
User equipment. further comprising means for transmitting a reference signal to the base station based on the one of the first reference signal sequence or the second reference signal sequence;
2. User equipment according to claim 1. The downlink control information is received in DCI (Downlink Control Information) format,
2. User equipment according to claim 1. The cyclic shift field is received in DCI (Downlink Control Information) format,
2. User equipment according to claim 1. the value of the cyclic shift field corresponding to the first reference signal sequence is one of 011, 100, 101, and 110;
the value of the cyclic shift field corresponding to the second reference signal sequence is one of 000, 001, 010, and 111;
2. User equipment according to claim 1. A first resource for transmission of the first reference signal sequence corresponds to even-numbered subcarriers and a second resource for transmission of the second reference signal sequence is to odd-numbered subcarriers. corresponding to
2. User equipment according to claim 1. The cyclic shift α _λ for at least one of the first and second reference signal sequences associated with layer λ at slot n _s is

given by α _λ =2πn _CS,λ /12, using
2. User equipment according to claim 1. a length of at least one of the first reference signal sequence and the second reference signal sequence is half a length of a legacy demodulation reference signal (DMRS) sequence;
2. User equipment according to claim 1. each length of the first reference signal sequence and the second reference signal sequence is

and

is the resource block size in the frequency domain expressed as the number of subcarriers, and

as the maximum uplink bandwidth configuration

is
2. User equipment according to claim 1. a base station,
A means for transmitting downlink control information to user equipment (UE: User Equipment),
determining, based on the downlink control information, that a cyclic shift field corresponds to either a first reference signal sequence or a second reference signal sequence, depending on the value of the cyclic shift field;
The first reference signal sequence is a base sequence

by the cyclic shift α of

is defined by
The second reference signal sequence is a base sequence

by the cyclic shift α of

is defined by
The base station further
means for receiving a reference signal corresponding to one of the first reference signal sequence or the second reference signal sequence to which the cyclic shift field corresponds, based on the downlink control information;
base station. The downlink control information is transmitted in DCI (Downlink Control Information) format,
11. A base station according to claim 10. The cyclic shift field is transmitted in DCI (Downlink Control Information) format,
11. A base station according to claim 10. the value of the cyclic shift field corresponding to the first reference signal sequence is one of 011, 100, 101, and 110;
the value of the cyclic shift field corresponding to the second reference signal sequence is one of 000, 001, 010, and 111;
11. A base station according to claim 10. A first resource for transmission of the first reference signal sequence corresponds to even-numbered subcarriers and a second resource for transmission of the second reference signal sequence is to odd-numbered subcarriers. corresponding to
11. A base station according to claim 10. The cyclic shift α _λ for at least one of the first and second reference signal sequences associated with layer λ at slot n _s is

given by α _λ =2πn _CS,λ /12, using
11. A base station according to claim 10. a length of at least one of the first reference signal sequence and the second reference signal sequence is half a length of a legacy demodulation reference signal (DMRS) sequence;
11. A base station according to claim 10. each length of the first reference signal sequence and the second reference signal sequence is

and

is the resource block size in the frequency domain expressed as the number of subcarriers, and

as the maximum uplink bandwidth configuration

is
11. A base station according to claim 10. A method performed by a user equipment (UE), comprising:
receiving downlink control information from a base station;
determining based on the downlink control information that a cyclic shift field corresponds to either a first reference signal sequence or a second reference signal sequence depending on the value of the cyclic shift field; including
The first reference signal sequence is a base sequence

by the cyclic shift α of

is defined by
The second reference signal sequence is a base sequence

by the cyclic shift α of

is defined by
The method further comprises:
determining the one of the first reference signal sequence or the second reference signal sequence to which the cyclic shift field corresponds;
generating the one of the first reference signal sequence or the second reference signal sequence based on the downlink control information;
Method.

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