Communication device, communication method, and computer program for executing same

Abstract

A communication device, a method for operation of the communication arrangement and a computer program comprising instructions to cause a computer to execute the method for operation of the communication device are disclosed. The communication device comprises one or more digital controllable scatterer (DCS), a distribution circuit and a DCS control circuit, and is characterized in that the one or more digital controllable scatterer (DCS) is / are connected with the distribution circuit and the DCS control circuit. The distribution circuit is configured to distribute a respective base phase shift map to each of the one or more DCSs. And a DCS control circuit for operating each DCS of the one or more DCSs during a sequence of time intervals to provide a respective sequence of phase shift maps, the respective sequence of phase shift maps is obtained by applying, during each time interval of the sequence of time intervals, a respective additional phase shift in a sequence of additional phase shifts for a respective DCS to the base phase shift map assigned to the respective DCS.

Description

Technical Field

[0001] The present application relates to the technical field of communication devices, and more specifically, to a communication device including a digitally controllable scatterer and a method and a computer program for operating the communication device. Background Art

[0002] In the field of wireless communication technology, by providing multiple antennas in some or all communication nodes (CN), the capacity of the wireless channel between communication nodes can be increased. This technology is called multiple-input and multiple-output (MIMO) technology. For example, CN can be a base station (BS) or user equipment (UE). Compared with the single-input single-output (SISO) technology that provides a single antenna at each communication node, MIMO technology can utilize the spatial diversity of the electromagnetic wave communication channel to increase the channel capacity.

[0003] To further improve wireless communications, it has been proposed to move away from schemes that exploit channel diversity due to electromagnetic wave propagation in the environment of the communication nodes to schemes that can manipulate the communication channels to adapt to specific needs. This can be achieved by introducing programmable surfaces called digitally controllable scatterers (DCS), in which a large number of reflecting or scattering elements are provided on a large surface. For example, DCS can be implemented in the form of reflective intelligent surfaces (RIS), intelligent reflective surfaces (IRS), or large intelligent surfaces (LIS). The scattering phase shift of each element that makes up the surface can be controlled individually. In this way, the communication channel can be formed by adapting to the needs and environment.

[0004] Figure 1 Schematically shown are a DCS 100 , a first CN 101 and a second CN 102 . The CNs 101 , 102 may be part of a group of CNs including other CNs which may have similar features to those of the first CN 101 and / or the second CN 102 .

[0005] The DCS 100 includes a plurality of scattering elements 103, one of which is located at Figure 1The scattering element 103 is exemplarily indicated by reference numeral 104. The scattering element 103 is adjusted so that incident electromagnetic radiation, especially electromagnetic radiation in a specific frequency range for wireless communication, is reflected with an electronically controllable phase shift. Examples of scattering elements include antennas and metamaterials connected to phase shift circuits.

[0006] exist Figure 1 100 , the electromagnetic radiation emitted by the first CN 101 is schematically shown by dashed arrows. The electromagnetic radiation from the first CN 101 reflected by the DCS 100 to the second CN 102 is schematically shown by dashed arrows. The reflection of the electromagnetic radiation at the DCS 100 facilitates the communication channel from the first CN 101 to the second CN 102. The entire communication channel can be decomposed into two main components, namely a non-DCS channel 106, in which the electromagnetic radiation propagates from the first CN 101 to the second CN 102 without being reflected at the DCS 100, and a DCS channel 105, in which the electromagnetic radiation is reflected at the DCS 100. For resource allocation, it may be necessary to know the direct channel between the first CN 101 and the second CN 102 and the channel 105 via the DCS 105. Furthermore, it may be desirable to separate a signal component of a signal transmitted by the first CN 101 that is received by the second CN 102 via the non-DCS channel 106 from a signal component of a signal transmitted by the first CN 101 that is received by the second CN via the DCS channel 105 .

[0007] In an arrangement in which multiple DCSs similar to DCS 100 are provided, multiple communication channels may exist between first CN 101 and second CN 102. In addition to non-DCS channel 106, there is a DCS channel similar to DCS channel 105 via each DCS. Therefore, when first CN 101 transmits a signal, the signal received at second CN 102 may have a signal component received via each DCS channel in addition to a signal component received via a non-DCS channel.

[0008] In applications, it may be necessary to estimate each DCS channel as well as non-DCS channels. Knowing the contribution of each DCS to the communication channel helps design communication algorithms that exploit the presence of the DCS to improve downlink and uplink performance. However, estimating the contribution may result in undesirable training overhead, which reduces the resources allocated to communication. Since the reflective or scattering elements that make up the DCS are typically not connected to the radio frequency (RF) chain, the DCS can neither estimate the propagation conditions nor send pilots. This means that the contribution of each DCS to the communication channel can only be measured at the first CN 101 or the second CN 102 via a signal sent by either the first CN or the second CN. This complicates the task of characterizing the communication channel via each DCS.

[0009] Furthermore, when communication between the first CN 101 and the second CN 102 is performed using a plurality of different frequencies, each communication channel may need to be determined separately for each coherent frequency band.

[0010] In the prior art, techniques have been proposed that employ subsequent activation of individual DCSs and techniques that employ frequency modulation, wherein the phase shift provided by the scattering elements of the DCS is modulated in time, thereby obtaining a frequency offset of the electromagnetic radiation reflected / scattered at the DCS. However, techniques according to the prior art are inefficient in terms of time resource utilization for channel estimation and / or may have difficulties in frequency resource allocation associated therewith. The use of frequency modulation may result in relatively large spectral noise, since the phase shift that may be applied at the scattering elements of the DCS may be limited to a small number of different values ​​in order to simplify the implementation. This may impair the quality of the frequency modulation based on the DCS.

[0011] In other prior art, a code is used to create a phase modulation of the individual scattering elements of a DCS, wherein the phase shift provided by each scattering element in the DCS is modulated differently in time according to the codeword of the corresponding scattering element. In this technique, codewords are used that are orthogonal between different time intervals of each DCS and between different scattering elements of each DCS. Therefore, the number of codewords and the length of the codewords are in the order of the number of scattering elements of the DCS, requiring a very large number of very long codewords. In addition, applying different phase modulations to the phase shifts of the individual scattering elements in the DCS changes the scattering pattern of the DCS between time intervals, which may result in obtaining scattering patterns that are not desired from a signal-to-noise ratio point of view in certain time intervals. In addition, in solutions according to the prior art, applying DCS coding requires additional overhead because the DCS coding is applied during dedicated training. Summary of the invention

[0012] The present invention provides a communication device and method for communicating on multiple frequency resources, which helps to solve some or all of the above problems. In particular, in the embodiments disclosed herein, the channel quality of non-DCS and DCS communication channels can be measured on the same resource during communication, and the signals received via the non-DCS and DCS communication channels can be obtained when communicating through these signals. In addition, channel estimates of non-DCS and DCS communication channels can be determined by using information contained in the signal.

[0013] According to a first aspect, a communication device includes one or more digitally controllable scatterers (DCS), a distribution circuit and a DCS control circuit. The distribution circuit is used to distribute a corresponding basic phase shift pattern to each of the one or more DCSs. The DCS control circuit is used to operate each of the one or more DCSs during a time interval sequence to provide a corresponding phase shift pattern sequence, which is obtained by applying a corresponding additional phase shift in an additional phase shift sequence of the corresponding DCS to the basic phase shift pattern allocated to the corresponding DCS during each time interval in the time interval sequence.

[0014] In one possible implementation, each of the one or more DCSs includes a plurality of scattering elements. A basic phase shift diagram assigned to the corresponding DCS defines a corresponding phase shift value for each scattering element of at least a portion of the plurality of scattering elements of the corresponding DCS. For each time interval in the time interval sequence, applying a corresponding additional phase shift in an additional phase shift sequence of the corresponding DCS to the basic phase shift diagram assigned to the corresponding DCS includes: for each scattering element of at least a portion of the plurality of scattering elements, adding a corresponding additional phase shift in the additional phase shift sequence of the corresponding DCS for the corresponding time interval to a phase shift value of the corresponding scattering element defined by the basic phase shift diagram.

[0015] In one possible implementation, for at least one of the one or more DCSs, at least a portion of the plurality of scattering elements of the corresponding DCS is a first portion of the plurality of scattering elements of the corresponding DCS. The second portion of the plurality of scattering elements of the corresponding DCS provides a virtual DCS. The allocation circuit is used to allocate a basic phase shift diagram of the virtual DCS to the virtual DCS. The basic phase shift diagram of the virtual DCS defines a corresponding phase shift value for each scattering element in the second portion of the plurality of scattering elements. The DCS control circuit is used to add a corresponding additional phase shift in an additional phase shift sequence of the virtual DCS to each of the phase shift values ​​defined by the basic phase shift diagram of the virtual DCS for the scattering elements in the second portion of the plurality of scattering elements during each time interval in the time interval sequence. The additional phase shift sequence of the virtual DCS is different from the additional phase shift sequence of the corresponding DCS.

[0016] In one possible implementation, the allocating circuit is further configured to allocate a corresponding codeword in a set of codewords to each of the one or more DCSs. For each DCS, the additional phase shift sequence of the corresponding DCS is based on the codeword component sequence of the codeword allocated to the corresponding DCS.

[0017] In a possible implementation, the one or more DCSs are multiple DCSs, and each DCS is assigned a different codeword in the set of codewords.

[0018] In a possible implementation manner, the codewords in the group of codewords are at least one of orthogonal and semi-orthogonal.

[0019] In one possible implementation, for each of the one or more DCSs, each additional phase shift in the additional phase shift sequence of the corresponding DCS is selected so that by applying the corresponding additional phase shift to the basic phase shift map assigned to the corresponding DCS, a phase shift scattering map of the DCS is obtained, which phase shift scattering map corresponds to the product of the codeword component of the codeword assigned to the corresponding DCS and the basic scattering map of the DCS obtained when the DCS provides the basic phase shift map of the DCS.

[0020] In one possible implementation, the communication device further includes a signal component separation circuit. The signal component separation circuit is used to obtain reception information from one or more first communication nodes (communication nodes, CNs). The reception information is based on one or more first CNs receiving one or more transmission signals sent by one or more second CNs during a time interval sequence. The reception information includes a representation of at least a portion of one or more signals received by one or more first CNs in response to one or more second CNs sending one or more transmission signals during a time interval sequence. The signal component separation circuit is used to apply a transformation to the representation of at least a portion of the one or more signals received by the one or more first CNs to separate one or more signal components of at least a portion of the one or more signals received by the one or more first CNs via one or more DCSs.

[0021] In one possible implementation, the transformation is a linear transformation.

[0022] In one possible implementation, the communication device further includes a channel estimation circuit. The channel estimation circuit is used to calculate a channel estimate based on the received information and a set of codewords. For at least one DCS in the one or more DCSs, the channel estimate includes an estimate of at least one corresponding communication channel between at least one of the one or more first CNs and at least one of the one or more second CNs via at least one DCS in the one or more DCSs.

[0023] In one possible implementation, the channel estimation circuit is further configured to calculate a representation of one or more transmission signals sent by one or more second CNs based on the aggregate communication channel and the result of the transformation, and to calculate a channel estimate based on the calculated one or more transmission signals and the result of the transformation.

[0024] In one possible implementation, a time interval in the time interval sequence is a sub-interval of a coding time interval.

[0025] In one possible implementation, at least one of the one or more second CNs transmits a plurality of orthogonal frequency division multiplexing (OFDM) symbols during a coding time interval.

[0026] In one possible implementation, each of the one or more second CNs has one or more antennas. Each of the one or more second CNs transmits OFDM symbols corresponding to the total number of antennas of the one or more second CNs during each time interval in the time interval sequence.

[0027] In one possible implementation, the transformation is based on a set of conjugate codewords of the set of codewords.

[0028] In one possible implementation, at least one of the one or more second CNs transmits a single OFDM symbol during a coding time interval.

[0029] In one possible implementation, the additional phase shifts in the additional phase shift sequence are repeatedly applied during each of the plurality of coding time intervals. The received information is one or more first CNs receiving one or more transmission signals sent by one or more second CNs during the plurality of coding time intervals. The transform is applied to a representation of the received one or more transmission signals.

[0030] In one possible implementation, each of the one or more second CNs has one or more antennas. Each of the one or more second CNs transmits a single OFDM symbol during each coding time interval in a plurality of coding time intervals. The number of the plurality of coding time intervals corresponds to the total number of antennas of the one or more first CNs.

[0031] In one possible implementation, the transformation is based on a model of the phase changes caused by applying a sequence of additional phase shifts during the transmission of a single OFDM symbol.

[0032] In one possible implementation, the coding time interval corresponds to a sampling interval, wherein one or more signals received by one or more first CNs in response to one or more transmission signals sent by one or more second CNs are sampled.

[0033] In a possible implementation manner, at least one of the one or more first CNs is a user equipment, and at least one of the one or more second CNs is a base station.

[0034] In a possible implementation manner, at least one of the one or more first CNs is a base station, and at least one of the one or more second CNs is a user equipment.

[0035] According to a second aspect, in a communication method, a respective basic phase shift pattern is assigned to each of one or more DCSs. During a sequence of time intervals, each of the one or more DCSs is operated to provide a respective sequence of phase shift patterns obtained by applying a respective additional phase shift in a sequence of additional phase shifts of the respective DCS to the basic phase shift pattern assigned to the respective DCS during each time interval in the sequence of time intervals.

[0036] According to a third aspect, a computer program comprises instructions which, when executed on a computer, cause the computer to perform the method according to the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Embodiments will be described below with reference to the accompanying drawings, in which:

[0038] Figure 1 shows the communication channels in an arrangement comprising one DCS and two CNs;

[0039] Figure 2 A communication device is shown;

[0040] Figure 3 CN is shown;

[0041] Figure 4 A DCS is shown;

[0042] Figures 5a to 5d shows the configuration of the scattering surface of the DCS;

[0043] Figure 6 A timing diagram is shown illustrating an embodiment of a DCS applying a sequence of encoded scattering patterns during transmission of a plurality of orthogonal frequency division multiplexing (OFDM) symbols during a coding time interval;

[0044] Figure 7 A timing diagram is shown showing signals transmitted by the BS on subcarriers and signals received at the UE during OFDM symbols without DCS coding outside the coding time interval and coding during the coding time interval in the downlink SISO case;

[0045] Figure 8 A timing diagram is shown illustrating an embodiment of DCS applying a sequence of encoded scattering patterns during transmission of a plurality of downlink OFDM symbols during a coding time interval;

[0046] Fig. 9A timing diagram is shown showing signals transmitted by the BS on subcarriers and signals received at the UE during OFDM symbols without DCS coding outside the coding time interval and with DCS coding during the coding time interval in the case of downlink MIMO;

[0047] Fig.10 A timing diagram is shown illustrating an embodiment of DCS applying a sequence of encoded scattering patterns during transmission of a plurality of OFDM symbols in the uplink by a UE during a coding time interval;

[0048] Fig.11 A timing diagram is shown showing signals transmitted by a UE on subcarriers and signals received at a BS from the UE during OFDM symbols with no coding outside a coding time interval and DCS coding during the coding time interval in the case of uplink MIMO;

[0049] Fig.12 A timing diagram is shown illustrating an embodiment in which a DCS applies a coded scattering pattern sequence during one downlink OFDM symbol corresponding to a coding time interval;

[0050] Fig.13 A timing diagram is shown illustrating an embodiment in which a DCS applies a coded scattering pattern sequence during each of a plurality of OFDM symbols, each OFDM symbol corresponding to one of a plurality of coding time intervals;

[0051] Fig.14 A timing diagram is shown illustrating an embodiment in which a DCS applies a coded scattering pattern sequence during each of a plurality of OFDM symbols, each OFDM symbol corresponding to one of a plurality of coding time intervals;

[0052] Fig.15 A timing diagram is shown illustrating an embodiment of a DCS applying an encoded scatter pattern sequence during a sampling time interval corresponding to an encoding time interval;

[0053] Fig.16 The signaling in the downlink scenario according to the embodiment is shown, wherein the BS performs configuration steps and notifies the DCS and the UE using signaling after all configuration steps are completed;

[0054] Fig.17 The signaling in the downlink scenario according to the embodiment is shown, wherein the BS performs configuration steps and notifies the DCS and the UE using multiple signaling after each configuration step is completed;

[0055] Fig.18 The signaling in the downlink scenario according to the embodiment is shown, wherein one DCS performs configuration steps and notifies other DCSs and UEs using multiple signaling after each configuration step is completed;

[0056] Fig.19 The signaling in the uplink scenario according to the embodiment is shown, wherein the BS performs the configuration steps and notifies the DCS and the UE using signaling after all the configuration steps are completed;

[0057] Fig. 20 The signaling in the uplink scenario according to the embodiment is shown, wherein the BS performs configuration steps and notifies the DCS and the UE using multiple signaling after each configuration step is completed;

[0058] Fig.21 The signaling in the uplink scenario according to the embodiment is shown, wherein one DCS performs configuration steps and notifies other DCSs and UEs using multiple signaling after each configuration step is completed;

[0059] Fig. 22 , 23 and 24 show signaling in an embodiment where the configuration steps are performed by an additional logic entity. DETAILED DESCRIPTION

[0060] The present invention provides embodiments of a communication device, a communication method and a computer program using a digitally controllable scatterer (DCS). In the embodiments disclosed herein, during a sequence of time intervals, each of one or more DCSs is operated to provide a corresponding sequence of phase shift patterns, the sequence of phase shift patterns being obtained by applying a corresponding additional phase shift in a sequence of additional phase shifts of the corresponding DCS to a basic phase shift pattern of the corresponding DCS during each time interval in the sequence of time intervals.

[0061] The basic phase shift pattern of each DCS is modified simply by applying the additional phase shift, so that the resulting radiation pattern of the DCS is a phase shifted version of the pattern obtained when applying the basic phase shift pattern.

[0062] A sequence of phase shift patterns may be provided in terms of a code. In each time interval, only one scalar component is required per DCS to provide an additional phase shift for the DCS, which is the same for all scattering elements of the DCS. Therefore, it is sufficient to provide only one codeword for each DCS, and orthogonality or semi-orthogonality is only required between codewords of different DCSs, but not between individual scattering elements of one DCS. Therefore, relatively short codewords may be used, since the codeword length does not depend on the number of scattering elements, which is a desirable feature, since the number of elements may be quite large (hundreds / thousands).

[0063] Coding can be applied during data transmission, and more than one DCS can be active in each time interval, so that the overall overhead of DCS channel quality measurement can be reduced. In addition, in an embodiment, codes such as Hadamard codes can be used. In Hadamard codes, each component of the codeword is limited to a small number (two) of possible values. This means that each phase shift in the additional phase shift sequence is limited to a small number (two) of possible values. This can simplify the implementation.

[0064] Figure 2 FIG. 2 shows a schematic diagram of a communication device 200 according to an embodiment. The communication device 200 includes a plurality of DCSs 201, 202, 203 and a plurality of communication nodes (CNs) 204, 205, 206, 207. Figure 2 As shown, CN 204 may be a base station (BS), and CN 205-207 may be user equipment (UE) or a repeater. The communication channel between BS 204 and UE 205-207 is partially via DCS 201, 202, 203. The wireless signals between BS 204 and UE 205-207 are propagated via the non-DCS path shown by the dotted arrows and the DCS path shown by the solid arrows.

[0065] The present invention is not limited to Figure 2 An embodiment of a BS and multiple CNs is shown. For example, multiple CNs 204-207 may include more than one BS, or all CNs may be UEs. CNs may also include repeaters, IABs, and other network components. Typically, there may be K UEs and D DCSs. In addition to one or more BSs and one or more UEs, multiple CNs may also include one or more access points (APs).

[0066] Figure 3 : shows a schematic block diagram of a CN 300 according to an embodiment. The CN 300 may be a UE, such as Figure 2 One of the CNs 205-207 shown, or may be a BS, e.g. Figure 2 BS 204 is shown. CN 300 may include antennas 301 and 302. The number of antennas may be one or two. Figure 3As shown. In other embodiments, a greater number of antennas may be provided. Providing two or more antennas may enable communication to be performed according to multiple input, multiple output (MIMO) technology. In other embodiments, such as in an embodiment where CN 300 is a UE, a single antenna may be provided. However, a UE having more than one antenna may also be used.

[0067] The CN 300 may include a transmitting circuit 303 and a receiving circuit 304, which are connected to the antennas 301, 302 and may be used to transmit and / or receive pilot signals and data signals to transmit and / or receive various types of information. In addition, the CN 300 may include a computing circuit 305, which may include a processor and a memory. The computing circuit 305 may be used to execute various algorithms, as described below. The computing circuit 305 may be used to perform various types of data processing at the CN 300 when performing a communication method using the CN as described in detail below, so that the computing circuit 305 may be configured to include circuits for various purposes.

[0068] In an embodiment, the calculation circuit 305 may include an allocation circuit 306. In addition, the calculation circuit 305 includes a signal component separation and channel estimation circuit 307. The allocation circuit may include a basic phase shift diagram allocation circuit 306a, a codeword allocation circuit 306b, a coding time interval allocation circuit 306c, and a transmission signal allocation circuit 306d. The signal component separation and channel estimation circuit may include a signal component separation circuit 307a, and in an embodiment, a channel estimation circuit 307b.

[0069] The present invention is not limited to the embodiment in which the distribution circuit 306 is arranged in the CN. In other embodiments, the distribution circuit 306 may be arranged in the DCS, as will be described below with reference to Figure 4 Described in more detail. In yet another embodiment, the allocation circuit or at least a portion thereof may be arranged in a network entity different from the CN and the DCS. For example, the basic phase shift diagram allocation circuit 306a may be arranged in the DCS control entity, the codeword allocation circuit 306b and the coding time allocation circuit 306c may be arranged in the channel estimation entity, and the transmission signal allocation circuit 306d may be arranged in the CN. In some embodiments in which a channel estimation entity is provided, the signal component separation and channel estimation circuit 307 or at least a portion thereof may also be arranged in the channel estimation entity.

[0070] Furthermore, the present invention is not limited to the embodiment in which the allocation circuit 306 and the signal component separation and channel estimation circuit 307 are provided in all CNs of the communication device. For example, they may be provided in only one CN, which may be a BS or a UE.

[0071] Figure 4 A DCS 400 that can be implemented in the form of an intelligent reflective surface (IRS) or a reflective intelligent surface (RIS) is schematically shown. In an embodiment, some or all of the DCSs 201, 202, and 203 of the communication device 200 may have features corresponding to the features of the DCS 400. The DCS 400 includes a scattering surface 401 and a controller 402. The scattering surface 401 includes a plurality of scattering elements 407, one of which is exemplarily represented by reference numeral 408. The plurality of scattering elements 407 can be adjusted so that the scattering phase shift of the electromagnetic radiation of the scattering elements (hereinafter represented as "scattering elements 407") in the plurality of scattering elements 407 is electronically controllable. In some embodiments, each scattering element 407 may include an antenna-based scattering circuit and a phase shift circuit. The phase shift provided by the phase shift circuit can be electronically controlled to provide a scattering phase shift of the scattering element. In other embodiments, the scattering element 407 may include a metamaterial element for providing a scattering phase shift for electromagnetic radiation within a predetermined frequency range that can be electronically controlled. By controlling the scattering phase shift of the scattering element 407, the scattering direction of the electromagnetic radiation incident on the scattering surface 401 of the DCS and the phase of the scattered electromagnetic radiation can be controlled.

[0072] The DCS 400 may further include a controller 402. The controller 402 may include an interface circuit 403 and a computing circuit 404, the interface circuit being used to connect the controller 403 to a scattering element 407 of the DCS 400, the computing circuit may include a processor and a memory, so that the computing circuit 404 may be configured as a circuit for various purposes. The computing circuit 404 may include a distribution circuit 306, which may have a configuration as described above with reference to Figure 3 Specifically, the allocation circuit 306 may include a basic phase shift diagram allocation circuit 306a, a codeword allocation circuit 306b, a coding time interval allocation circuit 306c and / or a transmission signal allocation circuit 306d (see Figure 3 ). In addition, the calculation circuit 404 may include a DCS control circuit 405.

[0073] The present invention is not limited to Figure 4 In the embodiment shown, each of the DCSs 201, 202, 203 has a substantially planar scattering surface 401. In other embodiments, some or all of the DCSs may include scattering surfaces having a non-planar configuration, as will be described below with reference to Figure 5a , 5b and as described in 5c.

[0074] Figure 5a A scattering surface 501a is schematically shown, which can be used as Figure 4 4. An alternative to the scattering surface 401 of the DCS 400 is shown. The scattering surface 501a includes a plurality of scattering elements 407, one of which is illustratively indicated by reference numeral 408. The scattering surface 501a has a non-planar configuration, wherein a front side of the scattering surface 501a is a convex surface. The front side of the scattering surface 501a is the side on which electromagnetic radiation reflected at the scattering surface 501a is incident during operation of the DCS 400. For example, in embodiments, the scattering surface 501a may be mounted on a wall of a building. In these embodiments, the front side of the scattering surface 501a is the side of the scattering surface facing away from the wall.

[0075] Figure 5b A scattering surface 501b is schematically shown, which can be used as Figure 4 Another alternative of the scattering surface 401 of the DCS 400 is shown. The scattering surface 501b comprises a plurality of scattering elements 407, one of which is exemplarily indicated by reference numeral 408. The scattering surface 501b has a non-planar configuration, wherein the front side of the scattering surface 501b is concave.

[0076] Figure 5c A scattering surface 501c is schematically shown, which can be used as Figure 4 Still another alternative to the scattering surface 401 of the DCS 400 shown. The scattering surface 501c includes a plurality of scattering elements 407, one of which is exemplarily indicated by reference numeral 408. The scattering surface 501c has a non-planar configuration, wherein the front face of the scattering surface 501c includes portions with different curvatures. For example, the front face of the scattering surface 501c may include convex portions, concave portions, and / or saddle-shaped portions.

[0077] Furthermore, the present invention is not limited to embodiments in which the scattering surface of the DCS 400 is provided as a single piece. Figure 5d A scattering surface 501d is schematically shown, which can be used as Figure 4 4. Another alternative to the scattering surface 401 of the DCS 400 shown. The scattering surface 501d includes a plurality of DCS blocks 502, 503, 504, 505 that may be distributed. Thus, the scattering surface 501d is not provided as a single piece. The scattering surface 501d includes a plurality of scattering elements, wherein each of the DCS blocks 502-505 includes a subset of the scattering elements. The DCS blocks 502-505 may have a non-planar configuration, such as Figure 5dIn other implementations, some or all of the DCS blocks 502-505 may be planar. The scattering elements of the DCS blocks 502-505 may operate in a cooperative manner such that the scattering surface 501d is provided as a virtual DCS scattering surface.

[0078] Reference again Figure 2 , the controllable scattering phase shift of the scattering elements of each of the DCSs 201, 202, 203 provides a method to modify the scattering pattern of the corresponding DCS and thus modify the communication channel between the BS 204 and the UEs 205-207 in order to improve downlink and uplink communications. Knowing the contribution of each DCS 201, 202, 203 to the overall communication channel between the BS 204 and each UE 205-207 may be important for designing communication algorithms that exploit the presence of the DCSs 201-203 to improve downlink and uplink performance. The improvement achieved depends on the available channel state information (CSI).

[0079] The embodiments described herein provide a solution for estimating the contribution of each DCS201, 202, 203 to the overall communication channel between BS204 and UE 205-207. This may be a challenging task, especially when the scattering elements of DCS201-203 are not connected to the radio frequency (RF) chain. In this case, DCS201-203 can neither estimate the propagation conditions nor send pilot signals. This means that the contribution of each DCS201, 202, 203 to the entire communication channel can only be measured at any one of BS204 or UE 205-207 via a signal sent by any one of BS204 or UE 205-207. This complicates the task of characterizing the entire communication channel via each of DCS201, 202, 203.

[0080] In the following, the DCS will be denoted by the index d. The total number of DCSs will be denoted as D, and the number of scattering elements of DCS d will be denoted as S. d . The index k will be used to represent the user equipment (UE), and the total number of UEs will be represented as K.

[0081] DCS D'S d The phase shift map of each scattering element can be represented by the vector φ d The components of this vector are the scattering phase shifts provided by the individual scattering elements of DCS d. The controllable phase shift pattern configuration of the scattering elements provides a method to control the scattering pattern of the DCS and thus modify the communication channel between the BS and the UE in order to improve downlink and uplink communications. In the following, by providing a phase shift pattern at DCS d consisting of φd The scattering diagram obtained by using the phase shift diagram represented by F d (φ d ). In the downlink, the signal received from the BS at the kth UE can be modeled as

[0082]

[0083] Among them, y 0,k represents the signal received via a non-DCS path, Denotes the signal received via DCS d. In the uplink, a model similar to that in equation (1) can also be used to describe the signal received at the BS from the kth UE. Observe y k Only information about the aggregate received signal is provided, i.e. the sum of the contributions of all DCS and non-DCS paths. Of particular interest is obtaining the signal component y received via the non-DCS channel 0,k and the signal components from D DCSs (i.e. ) related decomposition information, as this helps in knowing the contribution of each DCS and therefore helps in estimating the communication channel via each DCS.

[0084] The present invention provides a DCS coding scheme that enables a receiver to receive a signal y using only the set described in equation (1) k and the knowledge of the codes used at different DCSs to obtain the received non-DCS signal component y 0,k and all signal components received through D DCS Estimates.

[0085] In addition, the present invention provides a method for using the obtained signal A method for estimating non-DCS and DCS channels. In an embodiment, this can be done when these signals carry data information rather than training or pilot signals. The present invention provides a method for decomposing and obtaining the contribution of each DCS to the received signal and estimating non-DCS and DCS channels.

[0086] In an embodiment, some or all of the following steps may be performed.

[0087] 1. Basic Phase Shift Map Assignment Steps

[0088] In the basic phase shift diagram allocation step, a corresponding basic phase shift diagram φ is allocated to each DCS d=1,2,…,D d Basic phase shift diagram φ d Corresponding phase shift values ​​may be defined for at least a portion of the scattering elements of the DCS d. In an embodiment, the basic phase shift map φ dA corresponding phase shift value can be defined for each scattering element of DCS d. Therefore, a basic scattering pattern F is set for each DCS d (φ d ). The basic scattering pattern F of DCS d d (φ d ) is when DCS is used to provide the basic phase shift diagram φ d This can be achieved by controlling the scattering phase shifts of the scattering elements of the DCS d so that they provide a basic phase shift diagram φ d The encoding of each DCS will be applied on top of the basic scattering diagram. If the basic phase shift diagram is allocated by a network entity different from the DCS, signaling is performed to inform the DCS of the defined basic phase shift diagram. In an embodiment, the basic phase shift diagram allocation step can be performed by referring to Figure 3 and 4 The basic phase shift diagram distribution circuit 306a of the distribution circuit 306 is implemented.

[0089] 2. Codeword allocation steps

[0090] In the codeword assignment step, a corresponding codeword from a set of codewords is assigned to each DCS d=1, 2, ..., D. This can be achieved by selecting D orthogonal or semi-orthogonal codewords of length T and assigning one of the codewords to each DCS d=1, 2, ..., D. Different DCSs are assigned different codewords. These codewords are vectors of size 1×T and can be represented by a codebook structure c as in equation (2):

[0091]

[0092] In the following, using c d represents the codeword assigned to DCS d. The codeword is represented by the vector Indicates that the components of this vector define a series of codeword components Signaling may be performed to inform each DCS of its assigned codeword. In an embodiment, the codeword assignment step may be performed as described above with reference to Figure 3 and 4 The codeword allocation circuit 306b of the allocation circuit 306 executes.

[0093] 3. Coding time interval allocation steps

[0094] In the coding time interval allocation step, one or more coding time intervals are defined, which will be denoted as τ in the following. A coding time interval is a time interval during which all D DCS devices will apply the codewords selected in the codeword allocation step to the basic phase shift pattern selected in the basic phase shift pattern allocation step.

[0095] Signaling may be used to inform the DCS of one or more coding time intervals. As will be described in more detail in the following embodiments, since the codeword has a length T, each coding time interval includes T time intervals τ1, ..., τ T In the DCS operation steps described below, in each time interval τ1, ..., τ T Each period in will be based on the codeword component The additional phase shifts in the sequence of additional phase shifts are applied to the basic phase shift diagram φ of DCS d (d = 1, 2, ..., D) d Thus, a sequence of phase shift patterns of DCS d is provided. In embodiments with more than one coding time interval, the additional phase shift is repeatedly applied during each coding time interval. Thus, the duration of one coding time interval τ1 or a plurality of coding time intervals τ1, τ2, τ3, ... depends on the length T of the codeword and the time interval duration, the time interval during which DCS d=1,2,…,D applies each corresponding codeword component In an embodiment, one or more coding time interval allocation steps may be performed by referring to Figure 3 and 4 The coding time interval allocating circuit 306c of the allocating circuit 306 executes.

[0096] 4. Transmission signal allocation steps

[0097] In the transmission signal allocation step, the signal to be sent by one or more transmitting CNs during one coding time interval τ1 or multiple coding time intervals τ1, τ2, τ3, ... is defined. If the transmission is performed in the downlink, the signal sent by the BS is defined in the transmission signal allocation step. If the transmission is performed in the uplink, the signal sent by the UE is defined in the transmission signal allocation step. In some embodiments, multiple orthogonal frequency division multiplexing (OFDM) symbols are sent in one coding time interval, wherein the number of OFDM symbols corresponds to the total number of antennas for sending CNs. In other embodiments, a single OFDM symbol is sent in each of multiple coding time intervals, wherein the number of coding time intervals corresponds to the total number of antennas for sending CNs.

[0098] 5.DCS operation steps

[0099] In the DCS operation step, the time intervals τ1, ..., τ2, which are subintervals of a corresponding coding time interval τ1 or a plurality of coding time intervals τ1, τ2, τ3, are used as the subintervals of the corresponding coding time intervals. TEach period in will be based on the codeword component The additional phase shifts in the sequence of additional phase shifts are applied to the basic phase shift diagram φ of DCS d (d = 1, 2, ..., D) d , to provide a phase shift pattern sequence of DCS d. By for each scattering element in at least a portion of the scattering elements of DCS d (d=1, 2, ..., D), adding a corresponding additional phase shift for a corresponding time interval in the additional phase shift sequence of DCS d to the basic phase shift pattern φ d By adding the phase shift values ​​of the corresponding scattering elements defined above, an additional phase shift can be applied to the basic phase shift diagram of the DCS d.

[0100] The additional phase shift of DCS d is selected so that a phase shift scatter diagram of DCS d is obtained, which corresponds to the codeword components of the codeword assigned to DCS d and the phase shift scatter diagram of DCS d when DCS d provides the basic phase shift diagram φ d The basic scattering pattern φ obtained when d Thus, during one or more coding time intervals, a scattering pattern sequence of DCS d is obtained: In an embodiment, the operation of the scattering elements of each DCS in the DCS operation step may be controlled by the DCS control circuit 405 of the corresponding DCS. In addition, the over-the-air transmission of the transmission signal defined in the transmission signal definition step and the communication by the K CNs (e.g., UEs) are performed during one or more coding time intervals. k (k=1,…,K) reception (see equation (1)).

[0101] 6. Signal component separation and channel estimation steps

[0102] In the signal component separation and channel estimation steps, the received signal y k and the codewords used by the DCS (i.e., c1, c2, ..., c D ) to obtain the separated non-DCS and DCS signal components Receive signal y k The knowledge of can be provided by obtaining the received information. For example, in the downlink, y received at UE k k can be obtained from the received information at UE k. As another example, in the uplink, the received signal at the BS contains the contribution y from each UE k k In order to obtain the separated non-DCS and DCS signal components A transformation may be applied to the representation of the received signal. The transformation may be a linear transformation, which may be based on codewords c1, c2, ..., c DA set of conjugate codewords, or may be based on a model of the phase change caused by the additional phase shift sequence during the transmission of a single OFDM symbol. In an embodiment, the separation of non-DCS and DCS signal components may be obtained by referring to the above Figure 3 The signal component separation circuit 307a of the signal component separation and channel estimation circuit 307 performs the above operation.

[0103] Based on the separation of non-DCS and DCS signal components and the collective communication channel obtained via conventional training, then the representation of the transmission signal allocated in the transmission signal allocation step can be calculated. The transmission signal and the separated non-DCS and DCS signal components can be calculated based on In an embodiment, the channel estimate can be calculated by referring to Figure 3 The signal component separation and channel estimation circuit 307 is performed by the channel estimation circuit 307b.

[0104] Hereinafter, embodiments of the above-mentioned respective steps will be described in detail.

[0105] Example of a basic phase shift map assignment step

[0106] As described above, in the basic phase shift map assignment step, a basic scattering map F is provided for each DCS d=1,2,…,D. d (φ d ). Hereinafter, the method of obtaining F for each DCS d=1, 2, ..., D is described. d (φ d ) in three different ways:

[0107] (1) By randomly selecting φ d , randomly selecting an initial DCS phase configuration. An advantage of this embodiment is its simplicity. However, this embodiment may cause a degradation in the SNR of a signal received via the DCS unless selected from a set of predefined potential configurations identified for communication.

[0108] (2) Select φ based on information previously calculated or offline or previously obtained d Such prior information can be, for example, (i) the φ that previously produced good performance d Or (ii) statistical channel information or (iii) information about the main direction of communication between the DCS and one or both of the transceiver (TX) and the receiver (RX), such as offline channel estimation in a near-field scenario described in PCT / EP2021 / 057912, the disclosure of which is incorporated herein by reference.

[0109] (3) Maintain the phase that has been selected for communication and / or serving other nearby UEs (use the phase that has been set for communication and serving other UEs).

[0110] Embodiment of the codeword allocation step

[0111] As described above, in the codeword assignment step, D orthogonal or semi-orthogonal codewords of length T are selected and one of the codewords is assigned to each DCSd=1, 2, ..., D. In the following, two implementations of such sequences or codes that can be used are provided. The first implementation is based on Hadamard codes and the second implementation is based on Fourier matrices.

[0112] (1) Use Hadamard code. Select code words c1, c2, ..., c from the Hadamard matrix of size D+1. D . Therefore, the codeword length is T=D+1. One advantage of selecting codewords from a Hadamard matrix is ​​that in such a matrix, the elements take only two values ​​{+1,-1}, which can be easily achieved via the phase shift at the DCS scattering element by selecting the phase shift {0,π} respectively. Since the size of the Hadamard matrix is ​​D+1, there are D+1 codewords to choose from. The codewords (Hadamard matrix rows) corresponding to all entries equal to +1 are not assigned to any DCS. In this way, the codeword implicitly becomes the codeword for the non-DCS path. If the non-DCS path is not of interest (for example, if in the case of strong blocking, the non-DCS path can be ignored because its contribution is negligible), a Hadamard matrix of size D can be used, and the corresponding rows of the matrix can be assigned as c1, c2, ..., c D codewords. For some codeword lengths T, the required Hadamard matrix of size D or D+1 may not exist. In this case, one option is to use a Hadamard matrix of length The Hadamard code, where is the closest upper integer, and only a subset of the codewords of this Hadamard code are used. Other Hadamard-based structures with different code sizes are reported in the literature and are known.

[0113] As an example of a Hadamard-based structure, consider the case where D=3 of the non-DCS path needs to be estimated, so that T=D+1=4. The Hadamard matrix of size 4 is as follows,

[0114]

[0115] The codewords c1, c2, c3 assigned to DCS d=1, d=2, d=3 are the second to fourth rows of the Hadamard matrix in equation (3), respectively.

[0116] c1=[+1,-1,+1,-1] Equation (4)

[0117] c2=[+1,+1,-1,-1] Equation (5)

[0118] c3=[+1,-1,-1,+1] Equation (6)

[0119] (2) Use the DFT matrix. The codeword is selected from a DFT matrix of size D+1, so the codeword length is T=D+1. The codeword (DFT matrix row) corresponding to all entries equal to +1 is not assigned to the DCS, making the codeword implicitly the codeword of the non-DCS path. If the non-DCS path is not of interest (for example, if the non-DCS path can be ignored because its contribution is negligible in the case of strong blocking), a DFT matrix of size D can be used, and the corresponding rows of the matrix can be assigned to c1, c2, ..., c D codewords. One advantage of using a DFT matrix is ​​that the entries of such a matrix are of the form e jθ This facilitates the realization via DCS phase, since e can be achieved at the scattering element by applying a phase shift θ jθ In order to implement DFT-based phase shifting, the scattering elements of DCS may be required to provide multiple different phase shifts greater than two, while for Hadamard codes, the phase shift θ is further restricted to {0,π}.

[0120] Embodiments of the coding time interval allocation step and the transmission signal allocation step

[0121] These will be presented later concurrently with embodiments of the signal component separation and channel estimation steps, since embodiments of the coding time interval allocation step, the transmission signal allocation step, and the signal component separation and channel estimation steps are related and depend on the waveform used for communication.

[0122] Example of DCS operation steps

[0123] As described above, in the DCS operation step, over-the-air transmission and signal reception are performed, wherein each DCS d applies a corresponding coded scattering pattern sequence during each of one or more coding time intervals. In the following, the implementation of such a coded scatter pattern sequence at DCS d is explained.

[0124] As mentioned above, the scatter diagram of DCS d is represented by F d (φ d ), where φ d represents the phase shift diagram applied at the scattering element of DCS d. More specifically, φ d It can be expressed as follows with S d A vector of elements,

[0125]

[0126] in, is the phase shift configured at the &th scattering element of DCS d. As also mentioned above, c d represents a codeword of length T for DCS d, where It is c d No. When using Hadamard or DFT-based codes, the codeword components are of the form When By adding an additional phase shift to the phase of the scattering element The codeword components Applied to the scatter plot F d (φ d ) to obtain the top of the time interval Phase shift applied to DCS d as follows:

[0127]

[0128] The above formula represents the codeword components The coded phase shift at DCS d caused by . From equation (8), it can be seen that the phase of each scattering element is shifted by the same amount Therefore, apart from the phase shift, the scattering pattern of the DCS is not changed.

[0129] With S d The scattering pattern F of the DCS d of the scattering elements d (φ d ) is given by the diagonal matrix

[0130]

[0131] Among them, as mentioned above, It is in the DCS d The phase shift of the configuration at the scattering element, and Indicates the components of DCS d The amplitude change caused by , which is related to the radar cross section of the scattering element. The coded phase shift defined in equation (8) is used in the model in equation (9) Since the codeword component This produces the following encoded scatter diagram at DCS d:

[0132]

[0133] Therefore, due to DCS d consists of codeword components The resulting encoded scatter diagram can also be written as

[0134]

[0135] At time intervals 1, 2, ..., T for DCS Applying the codewords produces a sequence of encoded scatter patterns, described as

[0136]

[0137] or equivalently described as

[0138]

[0139] When the codeword components are in the form of hour.

[0140] Steps for allocating coding time intervals for downlink, SISO and DCS coding on multiple OFDM symbols, Embodiments of the transmission signal allocation step and the signal component separation and channel estimation step

[0141] As described above, in the code time interval allocation step, one or more code time intervals are defined during which the DCS will apply the encoded scattering pattern sequence. In this embodiment, a single code time interval τ1 is used. Given the code words c1, c2, ..., c2 defined in the code word allocation step, D , where, as mentioned above, the size of each codeword is T, thus defining the duration of τ1 to be equal to the duration of T OFDM symbols. The coding time interval τ1 is divided into Therefore, if the duration of an OFDM symbol is equal to μ OFDM seconds, then the duration of τ1 is equal to Tμ OFDM Seconds, subinterval The duration is equal to μ OFDM In addition, in this embodiment, as a part of the coding time interval allocation step, the coding interval τ1 is defined to start from the (l+1)th OFDM symbol.

[0142] In the transmission signal allocation step, the signal transmitted during the coding time interval τ1 is defined. In this embodiment, a single input single output (SISO) case is considered, where the BS has one transmitting antenna and each UE has one receiving antenna. The signal transmitted by the BS during the lth OFDM symbol is represented as x l (t).

[0143] Since the coding interval τ1 has been defined as starting from symbol l+1 and lasting for T OFDM symbols in the coding time interval allocation step, in the transmission signal allocation step, the signal x is defined as l+1(t), x l+2 (t), ..., x l+T In this embodiment, the signal transmitted during the coding interval τ1 is defined to be the same for all T OFDM symbols and equal to x′(t), so x l+1 (t) = x l+2 (t)=…=x l+T (t) = x′(t). Figure 6 The timing diagram shows the transmission signal during the coding time interval τ1 defined in this embodiment and the encoded scattering pattern sequence applied at DCS d. In this embodiment, DCS d applies the encoded scattering pattern sequence during the transmission of OFDM symbols l+1, l+2 until l+T corresponding to the coding time interval τ1. The signal transmitted during this time interval is equal to x'(t).

[0144] Since an OFDM waveform is used in this embodiment, the transmitted signal and the received signal can be expressed as follows. For an OFDM symbol composed of Nc orthogonal subcarriers, the transmitted signal x l The frequency domain representation of (t) is X l Can be written as Among them, X l,ω is a complex scalar representing the information sent on the ωth subcarrier and the lth OFDM symbol. Assuming that all non-DCS and DCS paths arrive within the cyclic prefix, after properly removing the cyclic prefix, since the BS sends X l The frequency domain representation of the signal received on the subcarrier ω of user k in the downlink can be written as

[0145]

[0146] Among them, H 0,k,ω and are scalars representing the non-DCS and DCS d-channel frequency responses of user k on subcarrier ω, respectively. Equation (14) has the same form as equation (1), but is written in the frequency domain.

[0147] In the following, the scatter diagram F will be described. d (φ d ) and the encoded scatter diagram For DCS channels For a given scatter diagram F d (φ d ), the DCS channel can be written as the product of three matrices

[0148]

[0149] in, is the channel between DCS d and UE k on subcarrier ω, is the channel between BS and DCS d on subcarrier ω. d In the case of a DCS of scattering elements, the matrix The size is 1×S d ,matrix The size is S d ×1. If the scatter plot F is not used d (φ d ), but uses the encoded scatter plot Then the channel can be written as

[0150]

[0151] Since this is done by replacing F d (φ d ) with And then use is a scalar and can be simplified as follows.

[0152]

[0153] Assume that all transmissions of interest occur within the channel coherence time (i.e., channel H 0,k,ω , and = 1 , then the signal received at UE k in the DCS operation step (which corresponds to over-the-air transmission and reception during the coding time interval τ1 and application of DCS coding, as described above) can be obtained using the scattering pattern F without coding. d (φ d ) is written as Equation (14) and using the encoded scatter diagram When written

[0154]

[0155] This is derived from equations (15), (16), and (17). To illustrate, Figure 7 A timing diagram of signals transmitted and received in the downlink is shown in FIG. The timing diagram shows the signal transmitted by the BS on subcarrier ω and the signal received on subcarrier ω of UE k during OFDM symbols without DCS coding (outside coding time interval τ1) and with DCS coding (within coding time interval τ1) in the downlink SISO case.

[0156] use represents the received downlink signal of OFDM symbols outside the coding time interval τ1, and uses Indicates the subinterval (which corresponds to the OFDM symbol ), equations (14) and (18) are rewritten as follows, respectively, where the signal is further rewritten into a matrix form, so

[0157]

[0158] and

[0159]

[0160] The use is that during the coding interval τ1, the transmitted signal is fixed to x′(t), which is the OFDM symbol, so it can be written in the frequency domain as Make Likewise, what is used in equation (20) is that at OFDM symbol l+t (i.e., at subinterval ), DCS d uses codeword components

[0161] In the following, the signal component separation and channel estimation steps will be described, wherein the received signal and the codewords used by the DCS (i.e., c1, c2, ..., c D ) to obtain the non-DCS signal component H 0,k,ω X′ ω and DCS signal components And further estimate the non-DCS channel H 0,k,ω and DCS channels If T observations As shown below,

[0162]

[0163] By using the above defined and code c for DCS d d With knowledge of , the signal received via DCS d during the entire coding interval τ1 without being affected by coding can be obtained, that is, Due to the orthogonality of the selected codewords (e.g. Hadamard or DFT as explained in the embodiments of the codeword assignment step), this can be obtained as follows:

[0164]

[0165]

[0166] Among them, the one used in the last step of equation (22) is

[0167]

[0168] And also

[0169]

[0170] Here, [] * Used to represent the conjugate of [], 1 d+1,T is a row vector of size T, where entry d+1 is equal to one and all other entries are equal to zero. A representation of the signal received at UE k during coding time interval τ1 is and The multiplication of τ / τ applies a conjugated codeword-based linear transformation to the representation of the signal received at UE k during the coding time interval τ1.

[0171] From equation (22), we can see that by calculating Can get

[0172]

[0173] This is the signal component received by UE k via DCS d. By calculating (This is also an application of linear transformation), we can get

[0174] H 0,k,ω X′ ω Equation (26)

[0175] This is a representation of the signal components received by UE k via non-DCS channels.Thus, by applying a linear transformation to the representation of the received signal, the signal components received via the respective DCS and via non-DCS channels can be separated.

[0176] By adding equation (26) and equation (25) calculated for all D DCSs, we can obtain

[0177]

[0178] In the above formula, is the aggregate channel observed before the coding time interval τ1. The aggregate channel can be obtained by conventional training, which can be performed at an earlier point in time to decode earlier symbols, or the aggregate channel can be calculated based on previously received information (e.g., via joint data and channel estimates within the OFDM symbols before the start of the coding time interval τ1). Using this aggregate channel With knowledge of , we can solve equation (27) to obtain X′ ω For all D DCSs, use the calculated X′ ω , we can solve equation (26) to obtain H 0,k,ω, we can solve equation (25) to obtain Thus, estimates of non-DCS and DCS channels can be obtained.

[0179] These estimates can later be used for further post-processing to enhance the ω In this embodiment, a trade-off is observed: the data symbol X′ ω Spanning multiple OFDM symbols, this reduces the communication rate but improves the SNR. Therefore, a higher modulation and coding scheme (MCS) can be used to avoid the rate loss caused by repeating data during the time slot of the coded DCS phase (i.e., during the coding time interval).

[0180] Steps for allocating coding time intervals for downlink, MIMO and DCS coding on multiple OFDM symbols, Embodiments of the transmission signal allocation step and the signal component separation and channel estimation step

[0181] In this embodiment, a downlink multiple input multiple output (MIMO) situation is described in which a BS has N transmitting antennas and a UE has multiple receiving antennas, wherein M k denotes the number of receive antennas at each UE k. As part of the code time interval allocation step, a single code time interval τ1 is defined during which DCS will apply the encoded scattering pattern sequence. Given the codewords c1, c2, ..., c defined in the codeword allocation step D , where, as mentioned above, the size of each codeword is T, thus defining the duration of τ1 equal to the duration of T*N OFDM symbols, and labeling the T subintervals of the coding time interval τ as In addition, each subinterval is further divided into N subintervals, where Used to represent subintervals Therefore, if the duration of an OFDM symbol is equal to μ OFDM seconds, then The duration is also equal to μ OFDM , The duration is equal to N*μ OFDM seconds, the duration of τ is equal to T*N*μ OFDM Second.

[0182] In addition, in this embodiment, as part of the coding time interval allocation step, it is defined that the coding time interval τ1 starts from the l+1th OFDM symbol, and each DCS is defined in the sub-interval Apply its corresponding codeword component

[0183] In the transmission signal allocation step, the signal to be sent during the coding time interval τ1 is defined. Using a vector x of length N l (t) represents the signal sent by the BS at time t and during the lth OFDM symbol. Since the coding time interval τ1 has been defined as starting from symbol l+1 and lasting for T*N OFDM symbols in the coding time interval allocation step, in the transmission signal allocation step, the signal x l+1 (t), x l+2 (t), ..., x l+TN (t) is defined as follows:

[0184]

[0185] therefore,

[0186]

[0187] This means that in the time subinterval The signal sent is equal to x′ n (t). In the above formula, x′ n (t) is a vector of length N, representing the signal sent by each transmitting antenna at time t. Figure 8 The timing diagram shows the transmission signal during the coding time interval τ1 defined in this embodiment and the encoded scattering pattern sequence applied at DCS d. DCS d applies the encoded scattering pattern sequence during the transmission of downlink OFDM symbols l+1, l+2 until l+T*N corresponding to the coding time interval τ1.

[0188] Since this embodiment uses OFDM waveform, the transmitted signal and the received signal can be expressed as follows. c OFDM symbol composed of orthogonal subcarriers, sending signal x l The frequency domain representation of (t) is X l Can be written as Among them, X l,ω is a complex matrix of size N×1, where N is the number of BS transmit antennas. l,ω represents the information sent on the ωth subcarrier at the lth OFDM symbol. Assuming that all non-DCS and DCS paths arrive within the cyclic prefix, after properly removing the cyclic prefix, since the BS sends X l The frequency domain representation of the signal received on subcarrier ω at user k in the downlink can be written as

[0189]

[0190] Among them, H 0,k,ω and It is M k×N matrix, M k is the number of antennas at UE k, and these matrices represent the non-DCS and DCS d channel frequency responses for user k on subcarrier ω. Equation (30) has the same form as equation (1), but is written in the frequency domain.

[0191] In the following, the scatter diagram F is explained d (φ d ) and the encoded scatter diagram For DCS channels For a given scatter diagram F d (φ d ), the DCS channel can be written as a cascade of three matrices as follows

[0192]

[0193] In this case of MIMO downlink, the channel between DCS d and UE k on subcarrier ω is and BS and DCS d The channel on subcarrier ω is The sizes are M k ×S d and S d ×N matrix. As mentioned above, S d is the number of scattering elements at DCS d. If the scattering pattern F is not used d (φ d ), but uses the encoded scatter plot Then the channel can be written as

[0194]

[0195] Since this is done by replacing F d (φ d ) with And get, so use is a scalar and can be simplified as follows.

[0196]

[0197] Assume that all transmissions of interest occur within the channel coherence time (i.e., channel H 0,k,ω , and = 1 , then the signal received at UE k in the DCS operation step (which corresponds to over-the-air transmission and reception during the coding time interval τ1 and application of DCS coding, as described above) can be obtained using the scattering pattern F without coding. d (φ d) is written as Equation (30) and using the encoded scatter diagram When written

[0198]

[0199] This is derived from equations (31), (32), and (33). To illustrate, Fig. 9 A timing diagram of signals transmitted and received in a downlink MIMO scenario is shown in FIG. The timing diagram shows the signal transmitted by the BS on subcarrier ω and the signal received on subcarrier ω of UE k during OFDM symbols without DCS coding (outside time interval τ1) and with DCS coding (within time interval τ1) in the downlink MIMO case.

[0200] use Represents the received downlink signal for OFDM symbols outside the interval τ1, and uses Indicates the subinterval The received downlink signal (which is used for OFDM symbols Received signal), equation (30) and equation (34) can be rewritten as follows, respectively, wherein the signal is further rewritten into a matrix form, so that

[0201]

[0202] and

[0203]

[0204] in, The size is M k The identity matrix, where used, is in the interval During this period, the transmitted signal is fixed at x′ n (t), which is an OFDM symbol, can be written in the frequency domain as X′ n,v is a complex matrix of size N×1, where N is the number of BS transmit antennas. n,ω Indicates that in the time subinterval The information sent on the ωth subcarrier. In equation (36), it is further used that in the time subinterval DCS d uses codeword components

[0205] In the following, the signal component separation and channel estimation steps will be described, wherein the received signal (in, n=1,2,...,N) (i.e., the signal received during the coding time interval τ1) and the codewords used by the DCS (i.e., c1, c2,..., c D ) to separate the non-DCS signal component H in the signal received by the UE 0,k,ω X′ n,ω and DCS signal components And further estimate the non-DCS channel H 0,k,ω and DCS channels T*N observations (in, n=1,2,…,N) and rewrite these observations as follows

[0206]

[0207] It can be seen that by using the above definition and code c for DCS d d With knowledge of , the signal received via DCS d during the entire coding interval τ1 without being affected by coding can be obtained, that is, Due to the orthogonality of the selected codewords (eg Hadamard or DFT as explained in the embodiments of the codeword assignment step), this can be obtained as follows.

[0208]

[0209] The last step in equation (38) uses

[0210]

[0211] And also

[0212]

[0213] in, M is all zeros k ×M k Matrix. Here, [] * Used to represent the conjugate of [], The size is M k (D+1) row vector, where the entries are d*M k +i is equal to one, and all other entries are equal to zero. The multiplication is based on a linear transformation of the conjugated codeword components.

[0214] From equation (38), we can see that by calculating Can get

[0215]

[0216] By calculation Can get

[0217] H 0,k,ω [X′ 1,ω ,X′ 2, ω,…,X′ N,ω ]. Equation (42)

[0218] Therefore, by applying a linear transformation based on the conjugated codeword components, signal components received by the UE via the non-DCS channel and via each DCS can be separated from each other.

[0219] By adding equation (42) and equation (41) calculated for all D DCSs, we can obtain

[0220]

[0221] In the above formula, is the aggregate channel observed before the time interval τ1. This channel can be obtained via conventional training, which can be performed at an earlier point in time because earlier symbols need to be decoded, or it can be calculated based on previously received information (e.g., via joint data and channel estimates within the OFDM symbols before the start of the coding time interval τ1). Using the aggregate channel With knowledge of , we can solve equation (43) to obtain [X′ 1,ω ,X′ 2, ω,…,X′ N,ω ]. For all D DCSs, use the calculated [X′ 1,ω ,X′ 2, ω,…,X′ N,ω ], we can solve equation (42) to obtain H 0,k,ω , we can solve equation (41) to obtain For example, by multiplying [X′ 1,ω ,X′ 2,ω ,…,X′ N,ω ] is the inverse or pseudo-inverse of ]. Thus, estimates of the non-DCS and DCS channels are obtained. These estimates can later be used for further post-processing to enhance the accuracy of [X′ 1,ω ,X′ 2,ω ,…,X′ N,ω ] is decoded. In this embodiment, there is a trade-off: the data symbol [X′ 1,ω ,X′ 2,ω ,…,X′ N,ω] spans multiple OFDM symbols. This reduces the communication rate but improves the SNR. Therefore, a higher modulation and coding scheme (MCS) can be used to avoid the rate loss caused by repeating data during the time slot of the coded DCS phase (i.e., during the coding time interval).

[0222] Steps for allocating coding time intervals for uplink, MIMO and DCS coding on multiple OFDM symbols, Embodiments of the transmission signal allocation step and the signal component separation and channel estimation step

[0223] In this embodiment, an uplink multiple input multiple output (MIMO) situation is considered in which the BS has N receiving antennas and the UE has multiple transmitting antennas. k represents the number of transmit antennas at the kth UE. Therefore, for the uplink, a total of M= As part of the code time interval allocation step, a single code time interval τ1 is defined during which the DCS will apply the encoded scattering pattern sequence. Given the code words c1, c2, ..., c defined in the code word allocation step D , where, as mentioned above, the size of each codeword is T, so in this embodiment, the duration of τ1 is defined to be equal to the duration of T*M OFDM symbols. The coding time interval τ1 is divided into Each subinterval is further divided into M subintervals. Used to represent subintervals Therefore, if the duration of an OFDM symbol is equal to μ OFDM seconds, then The duration is also equal to μ OFDM , The duration is equal to M*μ OFDM , the duration of τ1 is equal to T*M*μ OFDM In addition, in this embodiment, as part of the coding time interval allocation step, the coding time interval τ1 is defined to start from the l+1th OFDM symbol, and each DCS is defined in the subinterval Apply its corresponding codeword component

[0224] In the transmission signal allocation step, the signal to be sent during the coding time interval τ1 is defined. k The vector x l,k(t) represents the signal transmitted by UEk at time t and during the lth OFDM symbol. Since the coding time interval τ1 has been defined as starting from symbol l+1 and lasting for T*M OFDM symbols in the coding time interval allocation step, the signal x for all users k=1,2,…K in the transmission signal allocation step is l+1,k (t), x l+2,k (t), ..., x l+TN,k (t) is defined as follows:

[0225]

[0226] therefore,

[0227] x l+m,k (t) = x l+M+m,k (t) = x l+2M+m,k (t)=…=x l+(T-1)M+m,k (t) = x′ m,k (t) Equation (45)

[0228] Where m = 1, 2, ..., M, k = 1, 2, ... K, which means that UE k is in the time subinterval The signal sent is equal to x′ m,k (t). In the above formula, x′ m,k (t) is the length M k A vector representing the signal sent by each transmitting antenna of user k at time t. Fig.10 The timing diagram shows the transmission signal during the coding time interval τ1 defined in this embodiment and the encoded scattering pattern sequence applied at DCS d. The timing diagram shows that DCS d applies the encoded scattering pattern sequence during the transmission of uplink OFDM symbols l+1, l+2 of UE k until l+TM corresponding to the coding time interval τ1. .

[0229] Since this embodiment uses OFDM waveform, the transmitted signal and the received signal can be expressed as follows. c OFDM symbol composed of orthogonal subcarriers, sending signal x l,k The frequency domain representation of (t) is X l,k Can be written as Among them, X l,k,ω The size is M k ×1 complex matrix, indicating the M at UE k on the ωth subcarrier at the lth OFDM symbol k Assuming that the signal components of all non-DCS and DCS paths from all users arrive at the cyclic prefix, after appropriately removing the cyclic prefix, since user k sends X l,kThe frequency domain representation of the uplink signal received from UE k on subcarrier ω can be written as

[0230]

[0231] Among them, H 0,k,ω and is N×M k Matrices. These matrices represent the non-DCS and DCS d-channel frequency responses for user k on subcarrier ω, respectively. Equation (46) has the same form as equation (1), but is written in the frequency domain.

[0232] In the following, the scatter diagram F is explained d (φ d ) and the encoded scatter diagram For DCS channels It is known that for a given scattering pattern F d (φ d ), the DCS channel can be written as a cascade of three matrices as follows

[0233]

[0234] In this case of MIMO uplink, the channel between DCS d and BS on subcarrier ω is And the channel between UEk and DCS d on subcarrier ω, that is They are N×S in size. d and S d ×M k As mentioned above, S d is the number of scattering elements at DCS d. If the scattering pattern F is not used d (φ d ), but uses the encoded scatter plot Then the channel can be written as

[0235]

[0236] Since this is done by replacing F d (φ d ) with And then use The fact that is a scalar simplifies as follows:

[0237]

[0238] Assume that all transmissions of interest occur within the channel coherence time (i.e., channel H 0,k,ω , and =1, then the signal received at the BS in the DCS operation step (which corresponds to transmitting and receiving over the air during the coding time interval τ1 and applying DCS coding as described above) can be obtained by using the scattering pattern F without coding. d (φ d ) is written as Equation (46) and using the encoded scatter diagram When written

[0239]

[0240] This follows from equations (47), (48), and (49). To illustrate, Fig.11 A timing diagram of signals transmitted and received in an uplink MIMO scenario is shown in FIG. The timing diagram shows signals transmitted by UE k on subcarrier ω and signals received from UE k on subcarrier ω at the BS during OFDM symbols without DCS coding (outside time interval τ1) and with DCS coding (within time interval τ1) in the uplink MIMO case.

[0241] use represents the received uplink signal of OFDM symbols outside the coding time interval τ1, and uses Indicates the subinterval The received uplink signal (which is used for OFDM symbols Received signal), equation (46) and equation (50) can be rewritten as follows, respectively, where the signal has been further rewritten into a matrix form. Therefore,

[0242]

[0243] and

[0244]

[0245] Among them, I N is the identity matrix of size N. Here we use the matrix with the interval During this period, the signal sent by user k is fixed to x′ m,k (t), which is an OFDM symbol, can be written in the frequency domain as X′ m,k,ω The size is M k ×1 complex matrix. k is the number of transmit antennas at the UE, and the matrix X′ m,k,ω Indicates that in the time subinterval The information sent from UE k on the ωth subcarrier. In addition, what is used in equation (52) is that in the time subinterval DCS d uses codeword components

[0246] Considering the contributions of all K users within the OFDM symbol outside the interval τ1, the received signal is obtained using equation (51) as follows:

[0247]

[0248] Here, is a matrix of size N × M. Considering the contributions of all K users within interval τ1, the received signal is obtained using equation (52) as follows:

[0249]

[0250] Here, is a matrix of size N×M.

[0251] In the signal component separation and channel estimation steps, the received signal is used (in, m=1,2,...,M) (i.e., the signal received during the coding time interval τ1), and using the codewords used by the DCS, i.e., c1, c2,..., c D , so as to obtain the non-DCS signal H for each user k 0,k,ω X′ m,k,ω and DCS signal And further estimate the non-DCS channel H 0,k,ω and DCS channels

[0252] The TM observations (in, m=1,2,…,M) and the received signal can be rewritten as follows:

[0253]

[0254]

[0255] The signal received by DCS d due to K users transmitting during the coding interval τ1 but not affected by the coding is,

[0256]

[0257] By using the above definition and knowledge of the codes used for DCS dc d Due to the orthogonality of the selected codewords (e.g. Hadamard or DFT as explained in the embodiments of the codeword assignment step), the signal can be obtained as follows:

[0258]

[0259] The last step in equation (57) uses

[0260]

[0261] And also

[0262]

[0263] Among them, 0 N is an N×N matrix of all zeros.

[0264] The size defined in the codeword allocation step is T, and each DCS is equal to μ OFDM / T seconds duration during which the codeword component is applied Therefore, the coding time interval τ1 is divided into T sub-intervals The duration of each subinterval is μ OFDM / T seconds. In this way, DCS can apply the encoded scattering pattern for the duration of one (e)th OFDM symbol. Fig.12 A timing diagram is shown in FIG. 1 , showing the allocation of the transmission and reception of the DCS-encoded scattering pattern and the signal. The timing diagram shows that the DCS d applies the encoded scattering pattern sequence during the lth downlink OFDM symbol corresponding to the coding time interval τ1. .

[0265] Assume that the codeword entries are of the form This is the case, for example, when a Hadamard or DFT-based codebook is used. Then the signal received from DCS d at UE k during the coding time interval τ1 can be written as follows: According to equation (57), by calculating Can get

[0266]

[0267] By calculation Can get

[0268]

[0269] Receiving Signals and The multiplication of is a linear transformation based on the conjugated codeword. By applying this linear transformation, the signal components received by the BS via each UE are separated.

[0270] After separating the signal components, the data (the matrices on the right side in equation (60) and equation (61)) are obtained. By adding equation (61) and equation (60) calculated for all D DCSs, we can obtain

[0271]

[0272] In the above formula, is the aggregate channel observed before the coding time interval τ1, as defined in equation (53). The aggregate channel can be determined via conventional training, which is performed at an earlier time because earlier symbols need to be decoded, or the aggregate channel can be calculated based on previously received information (e.g., via joint data and channel estimates within the OFDM symbols before the start of the coding time interval τ1). Using the aggregate channel With knowledge of , we can solve equation (62) to obtain

[0273]

[0274] For all D DCSs, using these, equation (61) can be solved to obtain [H 0,1,ω ,H 0,2,ω ,…,H 0,K,ω ], we can solve equation (60) to obtain For example, by multiplying X′ ω The inverse or pseudo-inverse of X′ is obtained. Therefore, estimates of non-DCS and DCS channels are obtained. These estimates can be used later for further post-processing to enhance the ω In this embodiment, there is a compromise: ω Data symbols in the form of span multiple OFDM symbols. This reduces the communication rate but improves the SNR, so a higher modulation and coding scheme (MCS) can be used to avoid the rate loss caused by repeating data during the time slot of the coded DCS phase (i.e., during the coding time interval).

[0275] The case of DCS coding on a single OFDM symbol and the coding time interval allocation step in the downlink SISO scenario Embodiments of the steps of transmission signal allocation, signal component separation and channel estimation

[0276] As described above, in the coding time interval allocation step, one coding time interval τ1 or multiple coding time intervals τ1, τ2, τ3, ... are defined during which the DCS will apply the encoded scattering pattern sequence. In this embodiment, there is a single coding time interval τ1, whose duration is equal to the duration of one OFDM symbol. Therefore, if the duration of one OFDM symbol is equal to μ OFDM seconds, then the duration of the coding time interval τ1 is also equal to μ OFDM Furthermore, in this embodiment, as part of the coding time interval allocation step, a coding time interval τ1 is defined to correspond to the lth OFDM symbol.

[0277] In the transmission signal allocation step, the signal to be transmitted during the coding time interval τ1 is defined. In this embodiment, there is no restriction on the signal to be transmitted within this interval. Therefore, a signal with a duration of μ can be transmitted. OFDM Any OFDM symbol x l (t). Since code words c1, c2, ..., c D ,therefore

[0278]

[0279] in, Corresponds to the baseline case without DCS coding due to sending x l (t) and the theoretically received signal, where The phase shift caused by DCS coding is given by the term Capture, where

[0280]

[0281] Using equation (64) When considering the signal components received via all non-DCS paths and the signal components received via the DCS path, the signal received at UE k during the coding time interval τ can be written as

[0282]

[0283] By receiving the signal Multiply Can get

[0284]

[0285] expression and Corresponding to the received OFDM signal and The phases of these signals are represented by complex exponential and Modification. The effect of modifying the phase variation of the received OFDM signal has been studied in the OFDM literature analyzing the effects of receiver phase noise. Using known expressions from the OFDM and phase noise fields, the summation term in equation (67) can be written in the frequency domain. As mentioned above, in this embodiment, the downlink SISO case with one transmit antenna at the BS and one receive antenna at each UEk is considered. Signal It can be written in the frequency domain as follows:

[0286]

[0287] in,

[0288]

[0289] X is sent on subcarrier ω of OFDM symbol l l,ω A vector of information symbols for each subcarrier,

[0290]

[0291] is a diagonal matrix, where H 0,k,ω The channel frequency response on the subcarrier corresponding to the non-DCS channel ω between BS and UE k,

[0292]

[0293] in,

[0294]

[0295] Θ d′ [u] just Θ d′ The time-sampled version of (t) is given by

[0296]

[0297] The signal in equation (67) It can be written in the frequency domain as follows:

[0298]

[0299] Among them, X l As defined in equation (69),

[0300]

[0301] is a diagonal matrix. The channel frequency response caused by DCS d on subcarrier ω corresponding to the non-DCS channel between BS and UE k,

[0302]

[0303] in,

[0304]

[0305] Θ d [u]-Θ d′ [u] is Θ d (t)-Θ d′ The time-sampled version of (t) is given by

[0306]

[0307] Using equation (68) and equation (74), After the time multiplication of , the frequency domain representation of the signal received at user k during the coding time interval τ1 can be written as

[0308]

[0309] Therein, a matrix form representation is used in the final step.

[0310] From the above derivation, we can see that without multiplying (Simply set the terms in the above expression ), the received signal in the frequency domain is given by

[0311]

[0312]

[0313] Among them, G d It can be calculated according to equation (71): is of size N c Equation (80) can also be interpreted as multiplying the received signal by the codeword for the non-DCS channel, which, as described above, is implicitly assigned as a codeword with all entries equal to one.

[0314] By calculating in equation (79) (where d′=1, 2, …, D) and compare them with Superposition, we can get

[0315]

[0316] in,

[0317]

[0318] matrix is known, since it depends only on the coding used by the DCS. Therefore, the matrix can be calculated And perform the multiplication of its inverse, which uses the inverse in equation (81) Depend on Given, so as to obtain

[0319]

[0320] With the matrix Inverse The multiplication of is a linear transformation. As mentioned above, the matrix and its inverse are based on a model of the phase changes caused by applying an additional phase shift sequence during the transmission of a single OFDM symbol.By applying this linear transformation, the signal components received via the respective DCS are obtained.

[0321] The reversibility of is promoted by the codeword structure, which induces the matrix The strong diagonal components and matrices of The weakly off-diagonal components of . The diagonal of is composed of all ones,

[0322]

[0323] And, according to equation (77)

[0324]

[0325] In addition, in the matrix The matrix on the diagonal of has off-diagonal elements equal to zero, since this is the case for , and according to equation (77), it can be easily verified that

[0326]

[0327] In addition, the off-diagonal matrices in equation (82), i.e., G1, ..., G D and G d,d′ , where d≠d′, has a main diagonal equal to zero, since according to equation (72),

[0328]

[0329] where the last equation applies to Hadamard or DFT-based codes (or codes with codeword mean or zero) and

[0330]

[0331] The last equation is derived from the orthogonality of the codewords. Finally, the matrix The other diagonal items of G d (Ω≠0) and G d,d′≠d (Ω≠0) is expected to be weaker than The elements on the main diagonal of d (Ω≠0) and G d,d′≠d (Ω≠0) is a weighted sum which will give zero for unit weight but may deviate from zero for non-unit weight.

[0332] As described above, the signal components received via the non-DCS channel and the DCS channel Calculated according to equation (83). By adding all these terms, we get

[0333]

[0334] Channel Matrix is the channel for the OFDM symbol that arrived before the coding time interval τ1. This channel can be determined by known techniques and can be used to decode the previous symbol. With knowledge of , we can solve equation (89) to obtain X l , using X l With knowledge of , we can solve equation (83) to obtain Therefore, the non-DCS channel H can be estimated 0,k and DCS channels

[0335] By comparison Figure 6 and Fig.12 It can be seen that the advantage of encoding on one OFDM symbol is that less time is spent on the coding time interval τ1, in other words, the coding time interval τ1 is shorter.

[0336] The case of DCS coding on a single OFDM symbol and the coding time interval allocation step in the downlink MIMO scenario Embodiments of the steps of transmission signal allocation, signal component separation and channel estimation

[0337] As described in the previous SISO embodiment, an advantage of implementing DCS coding on a single OFDM symbol is that the duration of the coding time interval is shorter than coding on multiple OFDM symbols. The previous embodiment of coding on a single OFDM symbol can be extended to the downlink MIMO case by, for example, applying coding on one OFDM symbol per transmit antenna, as described below.

[0338] As in the previous embodiment, N is the number of transmit antennas of the BS. The UE has multiple receive antennas, where M k represents the number of receive antennas at each UE k. As part of the coding time interval allocation step, a plurality of coding time intervals τ1, τ2, τ3, ..., τ are defined. N During each of the plurality of coding time intervals, each DCS will apply a defined sequence of coded scattering patterns. Given N transmit antennas, in this embodiment, a sequence of N coding time intervals starting from OFDM symbol 1+1 and having a duration equal to the duration of N OFDM symbols is defined. For each of these N coding time intervals, each coding time interval corresponding to a corresponding OFDM symbol, a sequence of N coding time intervals labeled T subintervals of , where Used to mark the first Given the codewords c1, c2, ..., c defined in the codeword assignment step D , where, as mentioned above, the size of each codeword is T, so that in this embodiment, DCS is defined to apply DCS coding during each of n OFDM symbols. Fig.13 FIG. 1 shows a timing diagram showing the DCS d in relation to the plurality of coding time intervals τ1, τ2, τ3, ..., τ N The coded scattering pattern sequence is applied to each of the N OFDM symbols corresponding to a coding time interval in .

[0339] In the transmission signal allocation step, the signals sent from the BS antennas during N OFDM symbols are defined, each OFDM symbol corresponding to one of the multiple coding time intervals. These signals are labeled x l+1 (t), x l+2 (t), ..., x l+N (t), is a vector of size N. In this embodiment, during OFDM symbol l+n, only the nth transmit antenna is active. Therefore, in the subinterval During this period, only transmit antenna n transmits, and all other transmit antennas are silent. Therefore, the SISO processing explained in the previous section can be applied to estimate the channel from the active antenna to each receive antenna at each user. Specifically, the signals received during and before the plurality of coding time intervals can be used by applying the processing explained in the previous embodiment to each transmit-receive antenna pair. Therefore, the SISO processing as in the previous embodiment is performed, but the SISO processing is applied to each transmit-receive antenna pair.

[0340] By comparison Figure 8 and Fig.13 It can be seen that when the DCS codeword is Fig.13 When applied within an OFDM symbol, the duration of the coding interval is less than the time that a codeword spans multiple OFDM symbols.

[0341] In this embodiment, the encoded scattering pattern sequence is repeated over N OFDM symbols. The DCSs are informed of this repetition structure so that they apply the coded maps as required by this embodiment.

[0342] The case of DCS coding on a single OFDM symbol and the coding time interval allocation step in the uplink MIMO scenario Embodiments of the steps of transmission signal allocation, signal component separation and channel estimation

[0343] N represents the number of BS or receiving antennas. UE has multiple transmitting antennas, where M krepresents the number of transmit antennas at UE k. Therefore, the total number of transmitters for uplink is As part of the coding time interval allocation step, a plurality of M coding time intervals are defined, denoted as τ1, τ2, τ3, ..., τ M During each coding time interval, the DCS will apply the coded scattering pattern sequence. Given M transmit antennas, in this embodiment, a sequence of M coding time intervals starting from OFDM symbol l+1 and having a duration equal to the duration of M OFDM symbols is defined. Therefore, the duration of each coding time interval is one OFDM symbol. For each of the M OFDM symbols, define T subintervals of , where Used to mark the first Given the codewords c1, c2, ..., c defined in the codeword assignment step D , where, as described above, the size of each codeword is T, and DCS applies DCS coding during each of the M OFDM symbols in the M coding time intervals. Fig.14 FIG. 1 shows a timing diagram showing the DCS d in coding time intervals τ1, τ2, τ3, ..., τ M The coded scattering pattern sequence is applied to each of the M OFDM symbols .

[0344] In the transmission signal allocation step, multiple coding time intervals τ1, τ2, τ3, ..., τ M The signal sent during each period of k The vector x l+m,k (t) represents the signal transmitted by UE k during the l+mth OFDM symbol. In this embodiment, during OFDM symbol l+m, only one antenna transmits, and all other antennas are silent. In addition, each antenna is active only during a single OFDM symbol during multiple coding time intervals, so a total of M OFDM symbols are sufficient so that each of the total M transmit antennas can be active at least once during multiple coding time intervals. Since only one transmit antenna is active at a given time, this can apply the processing explained in the SISO embodiment to estimate the channel from the active antenna to each receive antenna at the BS. Specifically, the signal received at the BS during and before the coding time interval is used to obtain the desired channel estimate by applying the SISO processing explained in the previous two embodiments to each transmit-receive antenna pair.

[0345] In this embodiment, the encoded scattering pattern sequence is repeated over M OFDM symbols. The DCSs are informed of this repetition structure so that they apply the coded maps as required by this embodiment.

[0346] Steps for allocating coding time intervals and transmitting signals in the case of DCS coding within waveform samples in SISO Embodiments of the signal allocation step and the signal component separation and channel estimation step

[0347] In the above uplink and downlink embodiments, OFDM waveforms are described, which are the most commonly used waveforms in current cellular and Wi-Fi systems. However, the present invention is not limited to OFDM waveforms, and other waveforms may also be used. In this embodiment, a general implementation that can be applied to any waveform by applying DCS coding in continuous waveform samples is described for the SISO case.

[0348] In the coding time interval allocation step, a coding time interval τ1 is defined during which the DCS will apply the encoded scattering pattern sequence. In the present embodiment, there is one coding time interval τ1, whose duration is equal to the duration of one time sample. Furthermore, in the present embodiment, as part of the coding time interval allocation step, a coding time interval τ1 is defined to correspond to the uth time sample. The time sampled transmit signal for the uth time sample is defined as follows

[0349] x[u]=x(uT sam ) Equation (90)

[0350] Among them, T sam is the duration of one time sample (sampling time). Since the encoding time interval τ spans only one time sample, the duration of τ1 is equal to T sam Second.

[0351] In the transmission signal allocation step, the signal transmitted during the interval τ1 is defined. In this embodiment, there is no constraint on the signal transmitted within this interval. Therefore, any x[u] can be transmitted. Since the given codewords c1, c2, ..., c defined in the codeword allocation step D The size of is T, so each DCS is equal to T sam / T seconds duration during which the codeword component is applied Therefore, the coding time interval τ is divided into T sub-intervals τ1, τ2, ..., ...、τ T , the duration of each subinterval is T sam / T seconds. In this way, DCS is able to apply the encoded scattering pattern for the duration of one (uth) time sample. Fig.15 A timing diagram showing the allocation of transmission, DCS-encoded scattering pattern and signal reception is shown in FIG. 1 , which shows the DCS d applying the encoded scattering pattern sequence during the u-th time sample corresponding to the coding time interval τ1. .

[0352] Since the receiver is equal to T sam / T, so during the coding time interval τ, the receiver observes T time samples, which are marked as y[u′+1], y[u′+2], ..., y[u′+T], as shown in Fig.15 In the downlink scenario, signals x and y represent the signal sent from the BS and the signal received at the UE, respectively. In the uplink scenario, signals x and y represent the signal sent by the UE and the signal received by the BS, respectively.

[0353] Due to the allocation in the coding time interval allocation step and the transmission signal allocation step, in the time subinterval The signal received from DCS D during

[0354]

[0355] in, is from DCS d without coding (i.e., without using F d (φ d ))'s channel, is encoded from DCS d (i.e., using ) channels. h0 is used to represent non-DCS channels. The received signal including all non-DCS and DCS paths during the period is obtained as follows

[0356]

[0357] In the above equation, it is assumed that all non-DCS and DCS signals arrive at the same time. If this is not the case, then, for example, a Rake reception structure can be used.

[0358] In order to obtain for all D DCSs Perform signal component separation and channel estimation steps. d [u′+1],y d [u′+2],…,y d [u′+T] superposition, we can get

[0359]

[0360] The signal components received via DCS d can be obtained by superimposing the received signal Apply a linear transformation to obtain. The linear transformation is based on the known codewords of DCSd And by conjugating the codeword with the signal Multiply to apply

[0361]

[0362] Here, equations (23) and (24) are used, [] * Used to represent the conjugate of [], 1 d+1,T is a row vector of size T, where entry d+1 is equal to one and all other entries are equal to zero. From equation (94), we can see that by calculating Can get

[0363]

[0364] By calculation It can be obtained (due to the orthogonality of codewords)

[0365] h0x[u]. Equation (96)

[0366] Therefore, the signal components received via the non-DCS channels and via each DCS channel can be separated. By adding equation (96) and equation (95) calculated for all D DCSs, we can obtain

[0367]

[0368] In the above formula, is the aggregate channel observed before the time interval τ1. This channel can be determined via conventional training, which can be performed at an earlier point in time, as earlier symbols may need to be decoded. Alternatively, the channel can be calculated from previously received information (e.g., via joint data and channel estimates within the OFDM symbols before the start of the coding time interval τ1). Using this aggregate channel With the knowledge of , equation (97) can be solved to obtain x[u]. For all D DCSs, using the calculated x[u], equation (95) can be used to solve equation (96) to obtain h0 and Thus, estimates of the non-DCS and DCS channels are obtained. These estimates can later be used for further post-processing to enhance the decoding of x[u].

[0369] In this embodiment, the duration of the time interval τ1 is only one sample, which is much shorter than in the previous embodiment. In addition, the DCS coding is applied during the time sample. Therefore, the coding described in this embodiment can be used for any waveform.

[0370] Steps for allocating coding time intervals and transmitting signals in case of DCS coding within waveform samples in MIMO Embodiments of the signal allocation step and the signal component separation and channel estimation step

[0371] The previous embodiments can be extended to any MIMO system with N transmit antennas and M receive antennas by making the time interval τ1 span the duration of N samples and making only one antenna active at a given time sample. In this way, the SISO processing described in the previous embodiments can be applied to each transmit-receive (TX-RX) antenna pair.

[0372] Example of a DCS being subdivided into multiple DCSs

[0373] The previous embodiments can also be applied to a single DCS consisting of S scattering elements by creating D disjoint groups (not necessarily contiguous) of scattering elements to provide a virtual DCS. For example, S d / D scattering elements. The above embodiments can be applied by treating D non-overlapping groups as different DCSs. For example, a first group of scattering elements of a DCS can be treated as scattering elements of one DCS, while one or more second groups of scattering elements can be treated as virtual DCSs. For this purpose, an allocation circuit can be used to allocate a corresponding basic phase shift diagram of a virtual DCS to each group of scattering elements that provides a virtual DCS. The basic phase shift diagram of the virtual DCS defines a corresponding phase shift value for each scattering element in the corresponding group of scattering elements. The DCS control circuit is used to add the corresponding additional phase shift value in the additional phase shift sequence of the virtual DCS to the phase shift value of the scattering elements in the corresponding group of scattering elements defined by the basic phase shift diagram of the virtual DCS assigned to the corresponding group during each time interval in the time interval sequence. The additional phase shift sequences of the respective groups can be different, so that for each virtual DCS, the signal components received via the virtual DCS can be separate DCSs, and channel estimates can be calculated for each virtual DCS.

[0374] Signaling Examples

[0375] In the following, reference will be made to Figures 16 to 23 Describes the signaling that can be performed in an embodiment. For convenience, Figures 16 to 23 In the embodiment of the present invention, the same reference numerals are used to represent corresponding steps. In particular, the basic shift map allocation step is generally represented by the reference numeral 1601, the codeword allocation step is generally represented by the reference numeral 1602, the coding time interval allocation step is generally represented by the reference numeral 1603, the transmission signal allocation step is generally represented by the reference numeral 1604, the DCS operation step is generally represented by the reference numeral 1605, and the signal component separation and channel estimation step is generally represented by the reference numeral 1606. If some of the steps are performed by different entities, the reference numerals with additional letters a and b will be used. For example, if Fig.16 , 17, 18, 22 and 23, parts of the signal component and channel estimation steps may be performed by different entities, e.g. Fig.16 , 17 and 18 are performed by the UE and the BS, or as shown in Fig. 22 and 23 In addition, part of the DCS operation step 1605 may be performed by each DCS, such as Fig.18 and 21 shown.

[0376] Implementation of signaling in downlink scenario

[0377] Fig.16 An example of a downlink scenario is shown in which the BS performs a basic phase shift pattern allocation step 1601, a codeword allocation step 1602, a coding time interval allocation step 1603, and a transmission signal allocation step 1604. The BS notifies each DCS d=1, ..., D of its allocated codeword c d and the underlying scatter plot F d (φ d ), and informs each UE k=1,…,K of the codewords c1,…,c used by DCS D The BS also notifies each DCS d and UE k of a coding time interval τ1 or multiple coding time intervals τ1, τ2, ..., in particular the start time and duration of the coding time interval, and the coding structure during the coding time interval. Fig.13 In the described embodiment, the encoded scattering pattern sequence is repeated over multiple OFDM symbols. Therefore, the DCS and UE are informed accordingly. The BS also informs the UE of the signal structure during one or more coding time intervals. For example, in the above reference Figure 6 In the described embodiment, the same signal is repeated during the T OFDM symbols of a single coding time interval τ 1. Thus, the user is informed of this repetition structure, but does not need to specify the exact data to be sent.

[0378] In DCS operation step 1605, downlink communication is performed, wherein each DCS d applies a scattering pattern F outside one or more coding time intervals. d (φ d ), and during one or more coding time intervals, applying a method based on the encoded scattering pattern In the implementation, the DCS may be synchronized using a GPS signal. For example, such GPS-based synchronization is used in 5G to synchronize eNBs, and corresponding techniques may be used in embodiments to synchronize the DCS. In the signal component separation and channel estimation steps, the received signal and c1, ..., c Dand τ1, τ2, ... are used to separate the signal components received via each DCS and perform channel estimation.

[0379] exist Fig.17 Another embodiment of downlink signaling is shown in FIG. 1 , wherein the information about F is sent in different signaling exchanges performed after each of the basic phase shift pattern allocation step 1601, the codeword allocation step 1602, the coding time interval allocation step 1603, and the transmission signal allocation step 1604 is completed. d (φ d )、c1、……、c D , τ1, τ2, … and the encoded information during τ1, τ2, …

[0380] As another downlink signaling embodiment, Fig.18 An embodiment is shown in which DCS d performs a basic phase shift pattern allocation step 1601, a codeword allocation step 1602, a coding time interval allocation step 1603, and a transmission signal allocation step 1604.

[0381] Implementation example of signaling in uplink scenario

[0382] Fig.19 The uplink embodiment of the BS performing the basic phase shift pattern allocation step 1601, the codeword allocation step 1602, the coding time interval allocation step 1603 and the transmission signal allocation step 1604 is shown. The BS notifies each DCS d=1, ..., D of its allocated codeword c d and its underlying scatter plot F d (φ d ), and informs each UE k=1,…,K of the codewords c1,…,c used by DCS D The BS also notifies each DCS d and UE k of a coding time interval τ1 or multiple coding time intervals τ1, τ2, ..., in particular, the start time and duration of the coding time interval, and the coding structure during the coding time interval τ1 or multiple coding time intervals τ1, τ2, ... For example, in the above reference Fig.14 In the described embodiment, the encoded scattering pattern sequence is repeated over multiple OFDM symbols. Thus, this is sent to the DCS and the UE. The BS also informs the UE of the signal structure during one or more coding time intervals τ. For example, in the above reference Fig.10In the described embodiment, M OFDM symbols are repeated T times during one coding time interval τ1. Therefore, the user needs to know this repetition structure, but does not need to specify the exact data to be sent. The DCS can be synchronized using GPS signals. Such GPS-based synchronization is already used in 5G to synchronize eNBs. Corresponding techniques can be used to synchronize individual DCSs. In a DCS operation step 1605, uplink communication is performed, wherein each DCS d applies a scattering pattern F outside one coding time interval τ1 or multiple coding time intervals τ1, τ2, ... d (φ d ), and during a coding time interval τ1 or a plurality of coding time intervals τ1, τ2, ..., a method based on the encoded scattering pattern is applied. In the signal component separation and channel estimation step 1606, the received signal and c1, ..., c D and knowledge of τ1, τ2, … to perform channel estimation.

[0383] exist Fig. 20 Another embodiment of uplink signaling is shown in FIG. 1 , in which the F is sent in different signaling exchanges that occur after each step is completed. d (φ d )、c1、……、c D , τ1, τ2, ... and the information encoded during τ1, τ2, ... As another uplink signaling embodiment, Fig.21 It shows the situation where DCS d performs a basic phase shift pattern allocation step 1601, a codeword allocation step 1602, a coding time interval allocation step 1603 and a transmission signal allocation step 1604.

[0384] Embodiments of signaling when additional logical entities perform partial steps

[0385] Fig. 22 and Fig.23 Variants of the signalling embodiments are described as well as the integration of the scheme into a cellular communication network. Fig. 22 and 23 It shows that in addition to BS, UE and DCS, there are two additional logical entities involved in the process. These two entities are represented as DCS control entity and channel estimation entity (in Fig. 22 and 23 The channel estimation entity (abbreviated as “channel estimation entity (Ch.Est.Entity)”) may be an independent entity in the network or fully integrated into one or more of the BS, UE and DCS.

[0386] Fig. 22 and 23 A downlink scenario is shown, but additional logical entities may also exist and perform certain steps in the uplink scenario.

[0387] Fig.24 Describes Fig. 22 A variation of . Fig.24 In , one iteration for each coding time interval includes defining the interval, the signal to be sent during the interval, and performing DCS operations and signal transmission steps for the interval 1605. Once the iteration within each coding time interval is completed, the system can proceed to the signal separation and channel estimation steps. Figures 16 to 24 , a potential signal exchange is schematically illustrated. It should be noted that the signal exchange may be reordered, grouped and / or delayed in embodiments as long as the logical order is followed so that the required information appears at the processing entity when required.

[0388] The above description is only a specific implementation of the present application and is not intended to limit the scope of protection of the present application. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should belong to the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A communication device, characterized in that: include: One or more digitally controllable scatterers (DCS); a distribution circuit for distributing a corresponding basic phase shift pattern to each of the one or more DCSs; A DCS control circuit is configured to operate each of the one or more DCSs to provide a corresponding sequence of phase shift patterns during a sequence of time intervals, the corresponding sequence of phase shift patterns being obtained by applying a corresponding additional phase shift in a sequence of additional phase shifts of the corresponding DCS to the basic phase shift pattern assigned to the corresponding DCS during each time interval in the sequence of time intervals.

2. The communication device according to claim 1, characterized in that Each of the one or more DCSs includes multiple scattering elements, wherein the basic phase shift diagram assigned to the corresponding DCS defines a corresponding phase shift value for each scattering element of at least a portion of the multiple scattering elements of the corresponding DCS, and for each time interval in the time interval sequence, applying the corresponding additional phase shift in the additional phase shift sequence of the corresponding DCS to the basic phase shift diagram assigned to the corresponding DCS includes: for each scattering element in the at least a portion of the multiple scattering elements, adding the corresponding additional phase shift in the additional phase shift sequence of the corresponding DCS for the corresponding time interval to the phase shift value of the corresponding scattering element defined by the basic phase shift diagram.

3. The communication device according to claim 2, characterized in that: For at least one of the one or more DCSs, the at least a portion of the multiple scattering elements of the corresponding DCS is a first portion of the multiple scattering elements of the corresponding DCS, a second portion of the multiple scattering elements of the corresponding DCS provides a virtual DCS, the allocation circuit is used to allocate a basic phase shift diagram of the virtual DCS to the virtual DCS, the basic phase shift diagram of the virtual DCS defines a corresponding phase shift value for each scattering element in the second portion of the multiple scattering elements, and the DCS control circuit is used to add a corresponding additional phase shift in an additional phase shift sequence of the virtual DCS to each of the phase shift values ​​defined by the basic phase shift diagram of the virtual DCS for the scattering elements in the second portion of the multiple scattering elements during each time interval in the time interval sequence, the additional phase shift sequence of the virtual DCS being different from the additional phase shift sequence of the corresponding DCS.

4. The communication device according to any one of claims 1 to 3, characterized in that: The assigning circuit is further configured to assign a corresponding codeword from a set of codewords to each of the one or more DCSs, and for each DCS, the additional phase shift sequence of the corresponding DCS is based on a codeword component sequence of the codeword assigned to the corresponding DCS.

5. The communication device according to claim 4, characterized in that: The one or more DCSs are a plurality of DCSs, each DCS being assigned a different codeword from the set of codewords.

6. The communication device according to claim 4 or 5, characterized in that: The codewords in the set of codewords are at least one of orthogonal and semi-orthogonal.

7. The communication device according to any one of claims 4 to 6, characterized in that: For each of the one or more DCSs, each additional phase shift in the additional phase shift sequence of the corresponding DCS is selected so that by applying the corresponding additional phase shift to the basic phase shift pattern assigned to the corresponding DCS, a phase shift scattering pattern of the DCS is obtained, the phase shift scattering pattern corresponding to the product of the codeword components of the codeword assigned to the corresponding DCS and the basic scattering pattern of the DCS obtained when the DCS provides the basic phase shift pattern of the DCS.

8. The communication device according to any one of claims 1 to 7, characterized in that: It also includes a signal component separation circuit, which is used to obtain reception information from one or more first communication nodes (communication nodes, CNs), and the reception information is based on the one or more first CNs receiving one or more transmission signals sent by one or more second CNs during the time interval sequence, wherein the reception information includes a representation of at least a portion of the one or more signals received by the one or more first CNs in response to the one or more second CNs sending the one or more transmission signals during the time interval sequence, and the signal component separation circuit is used to apply a transformation to the representation of at least a portion of the one or more signals received by the one or more first CNs to separate one or more signal components of the at least a portion of the one or more signals received by the one or more first CNs via the one or more DCSs.

9. The communication device according to claim 8, characterized in that: The transformation is a linear transformation.

10. The communication device according to any one of claims 8 or 9, characterized in that: Also includes: and a channel estimation circuit for calculating a channel estimate based on the received information and the set of codewords, wherein the channel estimate comprises, for at least one of the one or more DCSs, an estimate of at least one corresponding communication channel between at least one of the one or more first CNs and at least one of the one or more second CNs via the at least one of the one or more DCSs.

11. The communication device according to claim 10, characterized in that: The channel estimation circuit is further configured to calculate a representation of the one or more transmission signals sent by the one or more second CNs based on the aggregate communication channel and the result of the transformation, and to calculate the channel estimate based on the calculated one or more transmission signals and the result of the transformation.

12. The communication device according to any one of claims 8 to 11, characterized in that: The time intervals in the sequence of time intervals are sub-intervals of a coding time interval.

13. The communication device according to claim 12, characterized in that: At least one of the one or more second CNs transmits a plurality of orthogonal frequency division multiplexing (OFDM) symbols during the coding time interval.

14. The communication device according to claim 13, characterized in that: Each of the one or more second CNs has one or more antennas, and each of the one or more second CNs transmits a number of OFDM symbols corresponding to a total number of the antennas of the one or more second CNs during each time interval in the sequence of time intervals.

15. The communication device according to any one of claims 8 to 14, characterized in that: The transform is based on a set of conjugate codewords of the set of codewords.

16. The communication device according to claim 12, characterized in that: At least one of the one or more second CNs transmits a single OFDM symbol during the coding time interval.

17. The communication device according to claim 16, characterized in that: The additional phase shifts in the sequence of additional phase shifts are repeatedly applied during each of a plurality of coding time intervals, the received information being based on reception by the one or more first CNs of one or more transmission signals sent by the one or more second CNs during the plurality of coding time intervals, the transformation being applied to representations of the received one or more transmission signals.

18. The communication device according to claim 17, characterized in that: Each of the one or more second CNs has one or more antennas, wherein each of the one or more second CNs transmits a single OFDM symbol during each coding time interval in the plurality of coding time intervals, and the number of the plurality of coding time intervals corresponds to the total number of the antennas of the one or more first CNs.

19. The communication device according to any one of claims 16 to 18, characterized in that: The transformation is based on a model of phase changes caused by applying the sequence of additional phase shifts during transmission of the single OFDM symbol.

20. The communication device according to claim 12, characterized in that: The coding time interval corresponds to a sampling interval, wherein the one or more signals received by the one or more first CNs in response to the one or more second CNs sending the one or more transmission signals are sampled.

21. The communication device according to any one of claims 8 to 20, characterized in that: At least one of the one or more first CNs is a user equipment, and at least one of the one or more second CNs is a base station.

22. The communication device according to any one of claims 8 to 20, characterized in that: At least one of the one or more first CNs is a base station, and at least one of the one or more second CNs is a user equipment.

23. A communication method, characterized in that: include: assigning a corresponding basic phase shift pattern to each of the one or more DCSs; Each of the one or more DCSs is operated during a sequence of time intervals to provide a corresponding sequence of phase shift patterns obtained by applying a corresponding additional phase shift in a sequence of additional phase shifts of the corresponding DCS to the basic phase shift pattern assigned to the corresponding DCS during each time interval in the sequence of time intervals.

24. A computer program, characterized in that The method comprises instructions which, when executed on a computer, cause the computer to perform the method according to claim 23.

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