COMMUNICATIONS DEVICE FOR FORMING SYMBOL ARRAYS - Patent application

Abstract

The present invention relates to a first communication device and a second communication device for shaping a symbol sequence in a wireless transmission. The first communication device (100) obtains a second symbol sequence based on a first symbol sequence and a set of weights, where the first symbol sequence is based on a radiation pattern (600i) from a set of radiation patterns (600a, 600b, ..., 600n) for the first communication device (100), and the weights are derived based on the first symbol sequence. Then, a set of antenna elements (106a, 106b, ..., 106n) is controlled according to the radiation pattern (600i) to transmit a set of information bits that are mapped to the second symbol sequence. This allows the second symbol sequence to be customized for the wireless environment, improving signal design and enabling smart radio with better performance. Furthermore, the present invention also relates to corresponding methods and computer programs.

Description

[Technical field]

[0001] The present invention relates to a first communication device and a second communication device for shaping a symbol sequence in a wireless transmission. Furthermore, the present invention also relates to a corresponding method and a computer program. [Background technology]

[0002] The use of media to facilitate the transmission and reception of information has recently attracted some attention, in this case manipulating and enhancing the signal carrying the information on its way to the destination, thereby allowing a more reliable radio link from the transmitter to the receiver. This therefore allows smart wireless environments with added new degrees of freedom, further improving the network performance. In those smart wireless environments, the environment is not a passive environment, but can be modified and customized to enhance the network capacity and the user experience. For this purpose, in particular so-called mirrors are used to allow favorable signal manipulation. According to such directionality, the use of so-called radio frequency (RF) mirrors mounted near or around one or more transmitting antennas allows so-called medium-based modulation (MBM). By using RF mirrors, the transmitted signal as it is emitted will be shaped before it reaches the destination. MBM has been proposed for wireless communication systems beyond 5G, such as 6G. MBM will emerge as an upcoming technology that may be an alternative and / or complementary to the modern communication paradigm for 5G and beyond networking.

[0003] In a conventional solution, a single antenna connected to an RF chain radiates electromagnetic waves at a given frequency. The transmitting antenna is surrounded by a set of RF mirrors. The radiated signal will pass through those RF mirrors before being emitted towards its destination. The information bits are passed to a mirror controller, which generates a signal that activates a mirror pattern corresponding to a given subset of bits based on the combination of the input bits. Summary of the Invention

[0004] It is an object of some embodiments of the present invention to provide a solution that alleviates or overcomes the shortcomings and problems of conventional solutions.

[0005] These and further objects are solved by the subject matter of the independent claims. Further advantageous embodiments of the invention are set forth in the dependent claims.

[0006] According to a first aspect of the present invention, the above and other objects are achieved by a first communications device, comprising: a set of antenna elements configured to operate to produce a set of radiation patterns; a processor, the processor comprising: obtaining a first sequence of symbols based on a radiation pattern of the set of radiation patterns; obtaining a set of weights associated with the first sequence of symbols; obtaining a second symbol sequence based on the first symbol sequence and the set of weights; and and controlling the set of antenna elements in accordance with the radiation pattern to transmit a set of information bits that are mapped to the second symbol sequence. This is accomplished by a first communication device.

[0007] Thus, the first communication device can also be considered to be a transmitter configured to transmit a set of information bits that are mapped to a second symbol sequence, the second symbol sequence being obtained based on the first symbol sequence and a set of weights.

[0008] A symbol constellation, as used herein, refers to a signal point selected from a set of signal points in a signal space that may be partially generated by the environment. A signal point may be understood to be a signal constellation. One example of a signal space is a two-dimensional complex plane, for which signal points may be formed as an in-phase and quadrature (I / Q) mapping of the signal space in the complex plane. It is also possible to form higher order multi-dimensional signal constellations.

[0009] A radiation pattern may be understood to be the directional dependence (e.g., angular) of the intensity of electromagnetic waves from an antenna element measured either in close proximity to the antenna element (e.g., in the near field) or in close proximity to a receiver (e.g., in the far field).

[0010] An advantage of the first communication device according to the first aspect is that it customizes the second symbol sequence to the radio environment, improving signal design and thereby enabling smart radio with improved performance, which may also be understood as weight enabled symbol shaping, i.e. controlling and adapting the environment for data transmission.

[0011] In one implementation of the first communication device according to the first aspect, each antenna element of the set of antenna elements is configured to operate to produce a plurality of radiation states, whereby the set of antenna elements operates to produce the set of radiation patterns.

[0012] In one implementation form of the first communication device according to the first aspect, the set of antenna elements is positioned within a range of a radiating element configured to radiate electromagnetic waves, and the set of antenna elements is a set of radio frequency mirrors.

[0013] A radiating element may be considered to be a means for radiating electromagnetic waves, such as, for example, an RF signal. This may be accomplished, for example, by connecting a conventional antenna to an RF chain, which is a cascade of electronic components necessary to generate and transmit an RF signal.

[0014] The advantage of this implementation is that the final symbol space can be generated by a single RF chain, thereby expanding the symbol space by the antenna elements receiving the RF signal from the radiating element. This in turn allows the transmitter device to be cheaper and more compact. It also allows the allocation of antenna elements to be distributed.

[0015] In one implementation of a first communication device according to the first aspect, obtaining the first symbol sequence includes: receiving a set of channel estimates from a second communication device, each channel estimate corresponding to a radiation pattern of the set of radiation patterns; determining the first symbol sequence based on a channel estimate from the set of channel estimates.

[0016] An advantage of this implementation is that the first symbol sequence can be generated, updated and optimized based on channel variations, allowing for faster and more reliable transmission.

[0017] In one implementation of a first communication device according to the first aspect, obtaining the first symbol sequence includes: receiving a set of reference signals associated with said set of radiation patterns from a second communications device; determining a set of channel estimates based on the received set of reference signals, each channel estimate corresponding to a radiation pattern of the set of radiation patterns; determining the first symbol sequence based on a channel estimate from the set of channel estimates; or Receiving the first symbol sequence from a second communication device.

[0018] An advantage of this implementation is that it may reduce the feedback overhead from the second communication device to obtain the first symbol sequence.

[0019] In one implementation of a first communications device according to the first aspect, determining the first symbol sequence includes: determining the first symbol sequence based on a channel estimate from the set of channel estimates and a source-based modulation.

[0020] Source-based modulation may be understood to be any conventional modulation scheme that modifies a digital signal based on information bits earlier in the RF chain. Examples include M-ary phase shift keying (e.g., BPSK and QPSK) and M-ary quadrature amplitude modulation (M-QAM) (e.g., 16QAM and 64QAM).

[0021] The advantage of this implementation is that by using source-based modulation as well as radiation pattern, it is possible to further extend the first symbol constellation using joint symbol construction, which leads to a larger symbol constellation that allows faster transmission, and also allows joint coding of the radiation pattern and the information bits that are coded by the error correction code.

[0022] In one implementation of the first communications device according to the first aspect, obtaining the set of weights includes: receiving a set of channel estimates from a second communication device, each channel estimate corresponding to a radiation pattern of the set of radiation patterns; determining the set of weights based on a channel estimate from the set of channel estimates and the first symbol sequence.

[0023] An advantage of this implementation is that it may reduce the feedback overhead from the second communication device to obtain the weights.

[0024] In one implementation of the first communications device according to the first aspect, obtaining the set of weights includes: receiving a set of reference signals associated with said set of radiation patterns from a second communications device; determining a set of channel estimates based on the received set of reference signals, each channel estimate corresponding to a radiation pattern of the set of radiation patterns; determining said set of weights based on a channel estimate from said set of channel estimates; or Weights from a second communication device The said set of The method includes receiving the

[0025] An advantage of this implementation is that it may reduce the feedback overhead from the second communication device to obtain the weights.

[0026] In one implementation of the first communication device according to the first aspect, obtaining the second symbol sequence includes: Mapping the first sequence of symbols to the set of weights to obtain the second sequence of symbols.

[0027] The mapping may in some cases be understood to be a linear mapping.

[0028] The advantage of this implementation is that it is possible to achieve the enhanced properties of the second symbol sequence, which allows for faster and more reliable transmission, with a low-complexity implementation through linear mapping.

[0029] In one implementation of the first communication device according to the first aspect, obtaining the second symbol sequence includes: After mapping the first symbol sequence to the set of weights, performing power control and phase shifting to obtain the second symbol sequence.

[0030] An advantage of this implementation is that the second symbol sequence can be formed with the aid of a phase shifter, which may enable a less complex and cheaper analog domain implementation or a hybrid digital-analog implementation.

[0031] In one implementation of the first communications device according to the first aspect, the second symbol sequence is one of M-PSK or M-QAM.

[0032] M is a positive integer.

[0033] An advantage of this implementation is that the weights are used to enable backward compatibility with existing communication systems that use the above modulation schemes, whereby the effective constellation received by the receiver is one of the legacy constellations.

[0034] According to a second aspect of the present invention, the above and other objects are achieved by a second communications device, the second communications device comprising: receiving a set of reference signals from a first communication device, said set of reference signals associated with a set of radiation patterns of a set of antenna elements; determining a set of channel estimates based on the received set of reference signals, each channel estimate corresponding to a radiation pattern of the set of radiation patterns; and determining a first symbol sequence based on a channel estimate from the set of channel estimates. This is accomplished by a second communication device.

[0035] An advantage of the second communication device according to the second aspect is that the second symbol sequence can be customized to the radio environment to improve signal design and thereby enable smart radios with improved performance.

[0036] In one implementation of the second communication device according to the second aspect, and transmitting the first symbol sequence to the first communication device.

[0037] In one implementation of the second communication device according to the second aspect, determining a set of weights based on a channel estimate from the set of channel estimates and the first symbol sequence; and and transmitting the set of weights to the first communication device.

[0038] According to a third aspect of the present invention, the above and other objects are achieved by a method for a first communications device including a set of antenna elements, said set of antenna elements being configured to operate to produce a set of radiation patterns, the method comprising: obtaining a first sequence of symbols based on a radiation pattern of the set of radiation patterns; obtaining a set of weights associated with the first sequence of symbols; obtaining a second symbol sequence based on the first symbol sequence and the set of weights; and controlling the set of antenna elements according to the radiation pattern to transmit a set of information bits that are mapped to the second symbol sequence. This is achieved by the method.

[0039] The method according to the third aspect may be extended to multiple implementations corresponding to multiple implementations of the first communication device according to the first aspect, such that an implementation of the method includes one or more features of a corresponding implementation of the first communication device.

[0040] The advantages of the method according to the third aspect are the same as those of a number of corresponding implementations of the first communications device according to the first aspect.

[0041] According to a fourth aspect of the present invention, the above and other objects are achieved by a method for a second communication device, the method comprising: receiving a set of reference signals from a first communication device, said set of reference signals associated with a set of radiation patterns of a set of antenna elements; determining a set of channel estimates based on the received set of reference signals, each channel estimate corresponding to a radiation pattern of the set of radiation patterns; and calculating a first symbol sequence based on a channel estimate from the set of channel estimates. This is achieved by the method.

[0042] The method according to the fourth aspect may be extended to multiple implementations corresponding to multiple implementations of the second communication device according to the second aspect, such that an implementation of the method includes one or more features of a corresponding implementation of the second communication device.

[0043] The advantages of the method according to the fourth aspect are the same as those of a number of corresponding implementations of the second communications device according to the second aspect.

[0044] According to a fifth aspect, the application provides a chip, which may be used for a first communication device and / or a second communication device, comprising at least one communication interface, at least one processor, and at least one memory, the communication interface, the processor, and the memory being interconnected using a circuit (possibly using a bus), and the processor calling instructions stored in the memory to perform a method according to the third or fourth aspect.

[0045] According to a sixth aspect, the application provides a first and / or second communications device including a memory and a processor, the memory configured to store program instructions, and the processor configured to invoke the program instructions in the memory to implement functionality of the first and / or second communications device in the first or second aspect.

[0046] According to a seventh aspect, the present application provides a non-volatile storage medium, the non-volatile storage medium storing one or more program codes, the program codes being executed by the first communication device and / or the second communication device causing the first communication device and / or the second communication device to perform steps of an associated method performed by the first communication device and / or the second communication device in the third aspect or the fourth aspect.

[0047] The present invention also relates to a computer program featuring a program code which, when executed by at least one processor, causes the at least one processor to perform any of the methods according to the embodiments of the present invention. Furthermore, the present invention also relates to a computer program product including a computer readable medium and a computer program, the computer program being contained in a computer readable medium including one or more of the following group: Read-Only Memory (ROM), Programmable ROM (PROM), Erasable PROM (EPROM), Flash memory, Electrically EPROM (EEPROM), and a hard disk drive.

[0048] Further applications and advantages of several embodiments of the present invention will become apparent from the following detailed description. [Brief description of the drawings]

[0049] The several accompanying drawings are intended to clarify and explain several different embodiments of the present invention. [Figure 1] 1 illustrates a block diagram of a first communication device according to an embodiment of the present invention. [Figure 2a] A number of different radiation patterns are illustrated. [Figure 2b] Two different arrangements of radiating elements and associated antenna elements are shown. [Diagram 3] 1 illustrates a method for a first communication device according to an embodiment of the present invention. [Figure 4] 1 illustrates a second communication device according to an embodiment of the present invention. [Diagram 5] 1 illustrates a method for a second communication device according to an embodiment of the present invention. [Figure 6] 4 illustrates a further embodiment of a second communication device. [Figure 7] 1 illustrates a wireless communication system in accordance with one embodiment of the present invention. [Figure 8] Also shown is one embodiment of the first communications device employing power control and phase shifting. [Figure 9] Also shown is one embodiment of the first communication device employing source-based modulation. [Figure 10] Also shown is one embodiment of the first communication device employing MIMO. [Figure 11] 1 illustrates achievable transmission rate versus SNR for several embodiments of the present invention. [Figure 12] 4 is a signal diagram illustrating an interaction between a first communication device and a second communication device. [Figure 13] 1 shows a flowchart of an algorithm for calculating a set of weights. [Figure 14] Two embodiments for shaping the symbol array are illustrated. [Figure 15] 1 shows the distribution of minimum pairing distances for a population of symbol sequences. [Figure 16] The performance of three different transmission schemes is shown. [Figure 17] 1 illustrates shaping of a symbol array using a set of weights. [Figure 18] 1 illustrates the rotation of edge points within a symbol array. [Figure 19] Performance results for several different solutions are presented. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] The symbol constellation of the MBM for a single transmit antenna and a single receive antenna described previously can have a small minimum pairing distance. The main reason is that the constellation symbols are randomly formed according to the channel distribution law given by the medium. In this way, the minimum pairing distance of the receive symbol constellation for the MBM varies with the medium and may be very small. This leads to the fact that the performance of a single-input single-output (SISO) MBM, i.e., the performance of a single transmit antenna surrounded by RF mirrors using a single antenna receiver, is worse than that of a conventional SISO channel using a SISO source-based modulation, i.e., quadrature amplitude modulation (QAM). This makes the MBM an unattractive candidate for a SISO channel.

[0051] Accordingly, the inventors have come to realise that improved signal processing solutions are needed to increase the spectral efficiency required for future wireless communication systems.

[0052] 1 shows an embodiment of a first communication device 100 configured to communicate in a plurality of communication systems. The first communication device 100 includes a set of antenna elements 106a, 106b, ..., 106n configured to operate to produce a set of radiation patterns 600a, 600b, ..., 600n. The first communication device 100 further includes a processor 108 configured to control the set of antenna elements 106a, 106b, ..., 106n via dashed control lines. Control signals may be formed in the processor 108 and transmitted via wired control lines to the antenna elements 106a, 106b, ..., 106n to adjust the state of the set of antenna elements 106a, 106b, ..., 106n. Also, a wireless solution is possible (not shown in the figure) in which wireless control signals are transmitted from the processor 108 to the set of antenna elements 106a, 106b, ..., 106n to control the state. The wired or wireless control signals may, in some embodiments, depend on information bits, which are then mapped to a set of radiation patterns 600a, 600b, ..., 600n. Thus, based on the input information bits, the control signals are modified to configure a given radiation pattern.

[0053] The radiation pattern of the set of antenna elements 106a, 106b, ..., 106n may be understood to be the directional dependence of the intensity of the electromagnetic waves from the antenna elements. The intensity of the radiation pattern may be measured at a number of different angles, such as azimuth and elevation. In addition to the direction, the radiation pattern may be measured close to the antenna elements (e.g., in the near field) or close to the receiver (e.g., in the far field). It should be noted that the activation pattern of the set of antenna elements 106a, 106b, ..., 106n is referred to as a radiation pattern. Thus, the term radiation pattern may be referred to as activation pattern in the following disclosure. The radiation pattern may also be understood to be a transmission beam or a radio beam.

[0054] Further, the radiating element 104 is connected to an RF chain block 124, which may be a cascade of electronic components required to generate and transmit an RF signal. The RF chain block 124 provides an RF signal to the radiating element 104, which is configured to radiate electromagnetic waves at a given frequency of the RF signal, but is not limited to such. Thus, the first communication device 100 may also use a multi-frequency or any multi-carrier scheme. The radiating element 104 is surrounded by a set of antenna elements 106a, 106b, ..., 106n, which may be of a number of different configurations or designs depending on the application. The radiated RF signal from the radiating element 104 is transmitted to the antenna elements 106a, 106b, ..., 106n. Set of 1, for design example purposes only, the radiating element 104 is surrounded by 16 antenna elements, which are arranged cylindrically around the radiating element 104. Nevertheless, other arrangements of antenna elements may be envisaged in terms of the number of antenna elements, the type of antenna elements, and in what order, how the antenna elements are selected and how they are arranged.

[0055] Furthermore, the first communication device 100 may also include a bit feeder block 120 configured to provide information bits for transmission to the second communication device 300. The information bits are provided by the bit feeder block 120 to a serial-parallel block 122 configured to convert the information bits from serial to parallel to modify the radiation pattern. After serial-parallel conversion, the information bits are provided from the serial-parallel block 122 to a weight processing block 132 controlled by the processor 108 via a dashed control line from the processor 108 to the weight processing block 132.

[0056] The processor 108 of the first communication device 100 may be referred to as, but is not limited to, one or more general purpose central processing units (CPUs), one or more digital signal processors (DSPs), one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), one or more programmable logic devices, one or more discrete gates, one or more transistor logic devices, one or more discrete hardware components, and one or more chipsets. Additionally, the processor 108 may be configured to control one or more of the other functional blocks of the first communication device 100.

[0057] According to some embodiments of the present invention, the processor 108 is configured to obtain a first symbol sequence based on a radiation pattern 600i (where i denotes an index number) of a set of activation patterns 600a, 600b, ..., 600n. Each activation pattern results in a corresponding radiation pattern. The processor 108 is further configured to obtain a set of weights associated with the first symbol sequence. The processor 108 is further configured to obtain a second symbol sequence based on the first symbol sequence and the set of weights associated with the first symbol sequence. The processor 108 is further configured to control the set of antenna elements 106a, 106b, ..., 106n according to the radiation pattern 600i to transmit a set of information bits that are mapped to the second symbol sequence.

[0058] In some embodiments, each antenna element 106n of the set of antenna elements 106a, 106b, ..., 106n is configured to operate to produce a plurality of radiation states, whereby the set of antenna elements 106a, 106b, ..., 106n operates to produce a set of radiation patterns 600a, 600b, ..., 600n. By multiple radiation states is meant two or more radiation states. Different solutions can be used to achieve the different radiation states. For example, in this regard, variable capacitance diodes can be used to control the antenna elements 106a, 106b, ..., 106n. Furthermore, the load, polarity, and impedance of the antenna elements can be controlled to control the radiation state. Also, changing the spatial position of the antenna elements 106a, 106b, ..., 106n changes the radiation state. This last example actually changes the physical location of the antenna elements, but still allows the generation of different radiation patterns observed from a second communication device 300 configured to receive RF signals from the first communication device 100. This may be understood as a variation of Space Shift Keying (SSK). The antenna elements 106a, 106b, ..., 106n may also impart a so-called metasurface (or any intelligent surface) to enable metasurface-based modulation.

[0059] FIG. 2a illustrates several different configurations or radiation patterns for a set of antenna elements 106a, 106b, ..., 106n arranged in a rectangular shape around the radiating element 104. The set of antenna elements 106a, 106b, ..., 106n may have several radiation states. In this exemplary diagram, three radiation states are shown for each antenna element 106a, 106b, ..., 106n. The radiation states can be generated by changing the load of the antenna elements, for example, by using two switches (such as diodes) for each antenna element. By changing the load, it is possible to obtain (a) an open radiation state (i.e., a radiation state in which both switches are open), (b) a closed radiation state (i.e., a radiation state in which both switches are closed), and (c) a half-open or half-closed radiation state (i.e., a radiation state in which only one of the switches is open or closed). The black dots illustrate antenna elements in a closed radiation state, the white dots illustrate antenna elements in an open radiation state, and the dots with vertical lines illustrate antenna elements in a semi-open radiation state or a semi-closed radiation state. By selecting different radiation states for the antenna elements 106a, 106b, ..., 106n, different radiation patterns can be obtained. For example, the configuration pattern or radiation pattern 600a in Fig. 2a is a first radiation pattern for the first communication device 100, the radiation pattern 600b in Fig. 2a is a second radiation pattern, the radiation pattern 600i in Fig. 2a is a third radiation pattern, etc.

[0060] The set of antenna elements 106a, 106b, ..., 106n is placed within the range of the radiating element 104 such that the set of antenna elements influences the propagation of the RF signal radiated by the radiating element 104. It should be noted that the range may also be considered as the state of the antenna elements as an additional dimension for the design. The set of antenna elements may be placed, for example, within the near field (including reactive or radiative near field) or the far field of the radiating element 104. The position of the set of antenna elements 106a, 106b, ..., 106n relative to the radiating element 104 influences the propagation model of the radiated radio waves, and therefore, by using a set of weights, it is possible to construct the second symbol sequence in a manner that is advantageous in terms of performance.

[0061] Thus, Fig. 2b illustrates two different designs of the set of antenna elements 106a, 106b, ..., 106n arranged within the range of the radiating element 104. The set of antenna elements 106a, 106b, ..., 106n are arranged around the radiating element 104 with the same shape as in Fig. 2a. Meanwhile, in example A in Fig. 2b, the antenna elements are arranged at a distance d1 from the radiating element 104, whereas in example B in Fig. 2b, the antenna elements are arranged at a distance d2 from the radiating element 104, with d2>>d1, Fig. 2b means that the radiation patterns are different for example A and example B due to the difference in distance from the radiating element 104. That is, in addition to the previous examples of radiation states such as open, closed, or half-open / half-closed by adjusting the switches, it is also possible to obtain additional radiation patterns by varying the positions of the set of antenna elements 106a, 106b, ..., 106n. The positions of the sets of antenna elements may be varied to be in the near field relative to the radiating element 104 and / or out of the near field relative to the radiating element 104. The sets of antenna elements 106a, 106b, ..., 106n may also be grouped such that the antenna elements in each group remain approximately the same distance from the radiating element 104, but the group has different distances to the radiating element 104. The arrangement of the sets of antenna elements may be made in any three-dimensional shape with regular as well as irregular internal distances between the sets of antenna elements 106a, 106b, ..., 106n.

[0062] In an implementation not shown, the set of antenna elements 106a, 106b, ..., 106n may be mounted beneath an outer shield of the radiating element 104, such as beneath the shield of a conventional base station. In such an example, the antenna elements are arranged on a roughly regular two-dimensional grid. Set of For a particular communication scenario, the antenna elements 106a, 106b, ..., 106n may be arranged Set ofThe size, shape and geometry of 106a, 106b, ..., 106n as well as the corresponding radiation conditions for each antenna element can be modified or adapted and optimized, thereby resulting in more favorable channel conditions.

[0063] In some embodiments, the set of antenna elements 106a, 106b, ..., 106n are controlled by positive intrinsic negative (PIN) diodes, also known as RF switches as mentioned earlier. If all of the PIN diodes in each antenna element are simultaneously turned on or off, then each antenna element will have two radiation states: a first radiation state in which the antenna element passes an incident wave when the PIN diode is open, and a second radiation state in which the antenna element reflects the incident wave when the diode is closed.

[0064] The set of antenna elements 106a, 106b, ..., 106n may be understood in some embodiments as a set of RF mirrors, which are devices that allow perturbations to the radio channel. These perturbations are controlled to convey information from the transmitter to the receiver. For example, the RF mirrors may be constructed by the above-mentioned PIN diodes and patch antennas, whereby the perturbations are controlled with the aid of the PIN diodes. The antenna elements may form an intelligent reflective surface (IRS), a large intelligent surface (LIS), a reconfigurable intelligent surface (RIS), a passive / active relay array (PRA), and a metasurface (MS). The disclosed invention may therefore be used for such arrangements. For such cases, the set of antenna elements 106a, 106b, ..., 106n may be arranged in an IRS, a LIS, a RIS, a PRA, and an MS, which may be arranged between the transmitter and the receiver. The antenna elements 106a, 106b, ..., 106n may be collocated or distributed.

[0065] All sets of multiple radiation patterns for a set of antenna elements are

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[0066] In embodiments, the first communication device 100 receives feedback from the second communication device 300. The first communication device 100 uses the feedback to, for example, adjust the weights according to the power constraints.

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[0067] Fig. 3 shows a flow chart of a corresponding method 200 that may be performed in a first communication device 100, such as the first communication device shown in Fig. 1. Thus, the first communication device 100 includes a set of antenna elements 106a, 106b, ..., 106n configured to operate to produce a set of radiation patterns 600a, 600b, ..., 600n and a processor 108 configured to control the set of antenna elements 106a, 106b, ..., 106n. The method 200, which may be performed by the processor 108, includes a step 202 of obtaining a first symbol sequence based on a radiation pattern 600i of the set of radiation patterns 600a, 600b, ..., 600n. The method 200 further includes a step 204 of obtaining a set of weights associated with the first symbol sequence. The method 200 further includes a step 206 of obtaining a second symbol sequence based on the first symbol sequence and the set of weights. The method 200 further comprises the step 208 of controlling the set of antenna elements 106a, 106b, ..., 106n according to the radiation pattern 600i to transmit the set of information bits that are mapped to the second symbol sequence.

[0068] Fig. 4 shows a second communication device 300 according to an embodiment of the present invention. The second communication device 300 may also be referred to as a receiver. In the embodiment shown in Fig. 4, the second communication device 300 includes a receiver block 302, a channel estimation block 304, and a first symbol alignment block 306, which are coupled to each other with communication means known in the art of the present invention. Furthermore, the receiver block 302 is coupled to an antenna or antenna array 308.

[0069] The processor 302 of the second communication device 300 may be referred to as one or more general purpose central processing units (CPUs), one or more digital signal processors (DSPs), one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), one or more programmable logic devices, one or more discrete gates, one or more transistor logic devices, one or more discrete hardware components, and one or more chipsets. The memory 306 of the second communication device 300 may be a read only memory, a random access memory, or a non-volatile random access memory (NVRAM). The transceiver 304 of the second communication device 300 may be a transceiver circuit, a power controller, an antenna, or an interface for communicating with other modules or devices. In some embodiments, the transceiver 304 of the second communication device 300 may be a separate chipset or may be integrated with the processor 302 into one chipset. However, in some embodiments, the processor 302, transceiver 304, and memory 306 of the second communications device 300 are integrated into a single chipset.

[0070] According to some embodiments, the receiver block 302 is configured to receive a set of reference signals from the first communication device 100 via the antenna 308. The set of reference signals is associated with a set of radiation patterns 600a, 600b, ..., 600n of the set of antenna elements 106a, 106b, ..., 106n of the first communication device 100. The channel estimation block 304 is configured to determine a set of channel estimates based on the received set of reference signals. Each channel estimate corresponds to a radiation pattern 600i of the set of radiation patterns 600a, 600b, ..., 600n of the first communication device 100. The first symbol alignment block 306 is configured to calculate a first symbol alignment based on a channel estimate of the set of channel estimates.

[0071] In some embodiments, one or more operations performed by the receiver block 302, the channel estimation block 304, and the first symbol alignment block 306 are executed by a processor 302 of the second communication device 300, which may be referred to as one or more general purpose central processing units (CPUs), one or more digital signal processors (DSPs), one or more application specific integrated circuits (ASICs), one or more field programmable gate arrays (FPGAs), one or more programmable logic devices, one or more discrete gates, one or more transistor logic devices, one or more discrete hardware components, and one or more chipsets. The processor may cooperate with a memory of the second communication device 300, which may be a read-only memory, a random access memory, a non-volatile random access memory (NVRAM), or any other suitable memory.

[0072] FIG. 5 illustrates a corresponding method that may be performed by a second communications device 300, such as the second communications device shown in FIG. 400 4 shows a flowchart of a method 400 for determining a first symbol sequence based on a channel estimate of a first set of antenna elements 106a, 106b, ..., 106n of the first communication device 100. The method 400 includes a step 402 of receiving a set of reference signals from the first communication device 100. The set of reference signals is associated with a set of radiation patterns 600a, 600b, ..., 600n of the set of antenna elements 106a, 106b, ..., 106n of the first communication device 100. The method 400 includes a step 404 of determining a set of channel estimates based on the received set of reference signals. Each channel estimate corresponds to a radiation pattern 600i of the set of radiation patterns 600a, 600b, ..., 600n of the first communication device 100. The method 400 further includes a step 406 of calculating a first symbol sequence based on a channel estimate of the set of channel estimates.

[0073] Fig. 6 shows a further embodiment of the second communication device 300. When transmitting pilots from the first communication device 100 to the second communication device 300 (e.g., in DL), the second communication device 300 receives the pilots at an antenna or antenna array 308. The received pilots are demultiplexed in a receiver block 302, i.e., resource demapped in the time domain, frequency domain, or code domain. The demultiplexed pilots are provided to a channel estimation block 304, which estimates a channel for a radiation pattern associated with a pilot based on the received pilots. The channel estimates are then provided to a first symbol arrangement block 306, which forms a first symbol arrangement based on the channel estimates. Based on the first symbol arrangement, weights are calculated in a weight calculation block 310 for a given design metric. Based on the weights and the first symbol arrangement, a second symbol arrangement is further formed in a second symbol arrangement block 318, for example by using a linear mapping. Using the second symbol constellation with the known symbols and their associated bit-to-symbol mapping demodulation (indicating which information bits are carried by different symbols) is performed on the received symbols in a demodulation block 312. The demodulation block 312 may calculate log-likelihood ratio (LLR) values ​​for the different symbols or bits as input to a decoder block 314. To calculate the LLR values, the demodulation block 312 may also use the channel estimates from the channel estimation block 304 as input. The symbols being demodulated are then Decoder BlockThe symbols are decoded at 314. An information sink block 316 receives the decoded symbols from the decoder block 314 for a desired application. In addition, a feedback signal is formed at a feedback generator 320 based on any combination of the channel estimate from the channel estimation block 304, the first symbol sequence from the first symbol sequence block 306, the weights from the weight calculation block 310, and the second symbol sequence from the second symbol sequence block 318, or an index of any of these parameters, which may include compression, transformation, or indexing based on a predefined table of these parameters. The feedback signal is transmitted to the first communication device 100.

[0074] It should be noted that in an embodiment when transmitting pilots in the reverse direction from the second communication device 300 to the first communication device 100 (e.g., in the UL), instead, the weights and the second symbol sequence may be calculated in the first communication device 100 using the same method as that used in the second communication device 300, thereby eliminating or reducing the feedback signal from the second communication device 300. In some cases, the first communication device 100 may inform the second communication device 300 about the second symbol sequence using a control channel.

[0075] In some embodiments, when forming the legacy symbol sequence, which may be implemented by selecting appropriate weights, there is no need to inform the demodulator block 312 and the decoder block 314 about the second symbol sequence, since the weights are calculated to generate a symbol sequence having the same alignment points as the legacy symbol sequence.

[0076] FIG. 7 illustrates a wireless communication system 500 according to an embodiment of the present invention. The wireless communication system in the present disclosure includes, but is not limited to, an LTE, a 5G, or any future wireless communication system. The wireless communication system 500 may include a first communication device 100 and a second communication device 300 configured to communicate in the wireless communication system 500. For simplicity, the wireless communication system 500 illustrated in FIG. 7 includes only the first communication device 100 and the second communication device 300. However, the wireless communication system 500 may include any number of first communication devices and any number of second communication devices without departing from the scope of the present invention.

[0077] In the wireless communication system 500 illustrated in Fig. 7, the first communication device 100 operates as or is included in a network access node, such as a gNB, while the second communication device 300 operates as or is included in a client device, such as a UE. However, it should be noted that the reverse situation is possible, i.e., the first communication device 100 operates as a client device and the second communication device 300 operates as a network access node. In an exemplary scenario, the first communication device 100 and the second communication device 300 can communicate between each other in the downlink (DL) and / or uplink (UL), for example, via the Uu interface.

[0078] A client device in this disclosure includes, but is not limited to, a UE such as a smartphone, a cellular phone, a cordless phone, a session initiation protocol (SIP) phone, a wireless local loop (WLL) station, a personal digital assistant (PDA), a handheld device with wireless communication capabilities, a computing device or other processing device connected to a wireless modem, an integrated access and backhaul node (IAB) such as an in-vehicle device, a wearable device, a device mounted on a mobile vehicle or automobile, a drone, a device-to-device (D2D) device, a wireless camera, a mobile station, an access terminal, a user unit, a wireless communication device, a station of a wireless local access network (WLAN), a wireless-enabled tablet computer, a laptop embedded device, a universal serial bus (USB) dongle, a wireless customer premises equipment (CPE), and / or a chipset. In an Internet of Things (IOT) scenario, a client device may represent a machine or other device or chipset that performs communication between other wireless devices and / or network equipment.

[0079] The UE may also be referred to as a mobile phone, cellular phone, computer tablet, or laptop with wireless capabilities. A UE in this context may be, for example, a portable, pocketable, handheld, computer-embedded, or vehicle-mounted mobile device that enables the mobile device to communicate voice and / or data with other entities, such as other receivers or servers, over a radio access network. The UE may be a station (STA), which is any device that includes an IEEE 802.11-compliant media access control (MAC) and physical layer (PHY) interface to a wireless medium (WM). The UE may also be configured for communication with 5G wireless technologies, such as 3GPP-related LTE and LTE-Advanced, WiMAX and its evolved standards, and NR.

[0080] A network access node in the present disclosure includes, but is not limited to, a NodeB in a Wideband Code Division Multiple Access (WCDMA) system, an evolved Node B (eNB) or evolved NodeB (eNodeB) in an LTE system, or a relay node or access point in a fifth generation (5G) network, or an in-vehicle device, a wearable device, or a gNB.

[0081] Further, a network access node may be referred to herein as a radio network access node, an access network access node, an access point, or a base station, such as a radio base station (RBS), which may be referred to as a transmitter, "gNB", "gNodeB", "eNB", "eNodeB", "NodeB", or "B node" depending on the technology and terminology used in some networks. A radio network access node may be a number of different classes of radio network access nodes, such as a macro eNodeB, a home eNodeB, or a pico base station, based on the transmit power and also the cell size due to the transmit power. A radio network access node may be a station (STA), which is any device that includes an IEEE 802.11 compliant MAC and PHY interface to the wireless medium. A radio network access node may also be a base station corresponding to a 5G wireless system.

[0082] In some embodiments, the power control and phase shifting are also employed, as illustrated in the block diagram in FIG. 8. Thus, obtaining the second symbol sequence includes performing power control and phase shifting to obtain the second symbol sequence after mapping the first symbol sequence to a set of weights. The symbol sequence shaping of the first symbol sequence is thereby implemented by two independent blocks, namely the power controller and weight processing block 132 and the phase shifter block 134. Both of these blocks are configured and controlled by the processor 108 through the dashed control lines extending from the processor 108. The power controller and weight processing block 132 allows to change the distance of the symbol points from the origin in the two-dimensional plane, and the phase shifter block 134 (or, equivalently, the time delay block) allows to rotate the symbols in the two-dimensional plane. The combination of these two operations allows to form the desired second symbol sequence. The phase shifter block 134 (or, equivalently, the time delay block) may be implemented in the analog domain, or may be implemented in conjunction with the antenna element, or may be implemented as part of the antenna element. The power controller and weight processing block 132 and the phase shifter block 134 may be configured for all of the multiple radiation patterns of the first communication device 100. The power controller or phase shifter may use quantized steps for configuration. For example, the power controller or phase shifter may be configured according to an equation in which the step size for power and / or phase adjustment changes according to the variation of the symbol sequence or channel.

[0083] In some embodiments, conventional source-based modulation is used to calculate the first symbol sequence, which is also illustrated in the block diagram in FIG. 9. Thus, calculating the first symbol sequence includes calculating the first symbol sequence based on a channel estimate of a set of channel estimates and the source-based modulation. Source-based modulation may be understood to be a conventional modulation scheme that modifies a digital signal based on information bits before passing through the RF chain 124. Examples of conventional modulation schemes include M-ary phase shift keying (e.g., BPSK and QPSK) and M-ary quadrature amplitude modulation (M-QAM) (e.g., 16QAM and 64QAM).

[0084] The first communication device 100 includes a bit splitter block 126, which is placed after the serial-parallel block 122 in Fig. 9. It is assumed that each symbol point of the source-based modulation allows m1 bits per signal point, i.e., m1 is equal to 2 and 4 for QPSK and 16QAM, respectively. Then, a set of radiation patterns is

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[0085] The first communication device 100 in FIG. 9 may also include an optional feed line 144. When the first communication device 100 includes the feed line 144, the feed line 144 allows the selection of symbols obtained by source-based modulation to also allow changing their weights in addition to the radiation pattern obtained by selecting the activation pattern for the set of antenna elements 106a, 106b, ..., 106n. The advantage of this implementation is that it is possible to jointly optimize the resulting hybrid second symbol sequence obtained by source-based modulation and multiple antenna elements (i.e. multiple different radiation patterns). This in turn allows the second symbol sequence to have improved performance.

[0086] If the first communications device 100 does not include a feed line 144 (this case is not shown in FIG. 9 ), it reduces the number of weights for optimization that can rely only on antenna elements, and therefore reduces the complexity of optimizing the second symbol sequence, but results in lower performance compared to a solution that uses a feed line 144.

[0087] The bit splitter block 126 also arranges the information bits, which may be a set of binary bits, into two information sequences of bits. The two information sequences of bits may be disjoint sets of information or disjoint sets of information. The first information sequence of bits is provided to a source-based modulator 142 and the second information sequence of bits is provided directly to a processor 108, which upon receiving the second information sequence of bits adapts the antenna elements 106a as well as the weights based on the second information sequence of bits.

[0088] Examples of source-based modulation include, but are not limited to, source modulation such as phase shift keying (PSK), e.g., binary PSK (BPSK) and quadrature PSK (QPSK), and quadrature amplitude modulation (QAM), e.g., 16QAM and 64QAM.

[0089] In some embodiments, we also use multiple-input multiple-output (MIMO), which is illustrated in the block diagram in Fig. 10. For further capacity increase, this solution can enhance conventional MIMO systems when using two or more RF chains in the first communication device 100. It should be noted that the example in Fig. 10 shows only two MIMO branches and their corresponding RF chains for simplicity, but the first communication device 100 may include any number of suitable MIMO branches.

[0090] Fig. 10 shows a situation where the first communication device 100 uses a source-based modulation of MIMO combination. In addition, the first communication device 100 includes a precoding block 152 arranged between the source-based modulation block 142 and the weight processing blocks 132 and 132', which are controlled by the respective processors 108 and 108' via dashed control lines. The source modulated bits from the source modulation block 142 are provided to the precoding block 152, which precodes the received symbols. The precoding may be adjusted based on the selected radiation pattern, or vice versa if the processors 108 and 108' are adapted to select the precoder. The above source modulations can be used. It is assumed that each symbol point of the source-based modulation is capable of carrying m1 bits per symbol point. That is, in the case of QPSK and 16QAM, m1 is equal to 2 and 4, respectively. The precoding in the first communication device 100 may be performed digitally, similar to precoding in LTE and NR, and the receiver, i.e., the second communication device 300, also receives a rank indicator (RI) and a precoding matrix index (PMI). Based on selecting the RI and PMI via a feedback line, the first communication device 100 can further adjust its antenna elements to generate a radiation pattern that enhances a given metric for quality of service (QoS).

[0091] A non-limiting example of a MIMO implementation is described herein for a better understanding of such implementation. As shown in FIG. 10, assume that there are two radiating elements 104 and 104', such that each radiating element is surrounded by a set of antenna elements. Then, consider two feedback bits transmitted from the second communication device 300 to the first communication device 100 in a control signaling, which informs the first communication device 100 to select and activate a suitable activation pattern. This feedback is shown as Feedback_1 in FIG. 10 and is provided to the precoding block 152. Consider a single rank transmission using different PMIs, i.e., RI=1. In the NR case, there are four indices with four different precoding matrices. Then, disclose a design using these precoding matrices with the proposed solution. To this end, in the disclosed solution, two additional feedback bits are transmitted in a control signaling from the second communication device 300 to the first communication device 100 for the selection of an activation pattern. This feedback is shown in FIG. 10 as Feedback_2 and is provided to weight processing blocks 132 and 132' and to respective processors 108 and 108'.

[0092] Table 1 shows one example of a design using such an NR precoding matrix in MIMO. The first column indicates the combining index, and there are a total of four feedback bits indicating 16 indices, as shown in the second column. The first two bits (in column 3) indicate the activation pattern, and the remaining two bits (in column 4) select the precoding matrix by which the modulated symbols obtained by the source-based modulation are precoded using the indicated bits in the feedback.

[0093] Figure 11 shows the bit rate per channel used (bpcu) as a function of SNR in dB. The dashed line shows the conventional baseline MIMO scheme using precoding, and the solid line shows the disclosed solution using precoding. It is observed that the disclosed solution provides a multiple dB power gain compared to the conventional solution. [Table 1] TIFF0007616738000014.tif78170

[0094] FIG. 12 shows a signaling diagram illustrating the interaction between a first communication device 100 and a second communication device 300 in a communication system 500 according to embodiments of the present invention.

[0095] In step I in FIG. 12, the first communication device 100 transmits to the second communication device 300 a set of reference signals (RS) or pilots corresponding to a set of radiation patterns (or activation patterns). In general, the first communication device 100 transmits at least one reference signal or pilot for each radiation pattern of the set of radiation patterns for the set of antenna elements. Non-limiting examples of reference signals are Sounding Reference Signals (SRS), Demodulation Reference Signals (DMRS) or Channel State Information Reference Signals (CSI-RS). It may also be envisaged to include new reference signals in future standards only for this particular application, such as for example Mirror State Information Reference Signals (MSI-RS) designed for this particular application. The RS may be transmitted using various sequences. One example includes mutually orthogonal sequences transmitted in time or frequency, in addition to code division of the pilot sequences. The use of antenna element dependent cover codes may also be considered. It is possible to transmit pilots for a subset of activation patterns or a subset of antenna elements to reduce pilot overhead. It should be noted that it is possible to perform a similar procedure, transmitting RS in the other direction from the second communication device 300 to the first communication device 100. This approach is more useful when having partial reciprocity in time division duplex or frequency division duplex, where partial reciprocity on UL and DL is preserved for angle and channel delay.

[0096] For an antenna element implemented with a PIN diode as described above, the complete set of multiple radiation patterns can be calculated using the

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[0097] In step II in Fig. 12, the second communication device 300 estimates a wireless channel for each radiation pattern of the set of radiation patterns based on the received set of reference signals, the estimated channel for each radiation pattern representing a constellation symbol in the received symbol constellation.

[0098] In some embodiments, the second communication device 300 may optionally signal the channel estimates 600a, 600b, ..., 600n directly to the first communication device 100, as illustrated by the dashed arrow extending from box II. In this case, the second communication device 300 does not need to execute the subsequent steps III to V in Fig. 12. The signaling of the channel estimates 600a, 600b, ..., 600n may be, for example, an index of the channel estimate mapped in a table, an index of the channel estimate indexed by a binary bit string, or an index of the channel estimate compressed or differentially represented based on a previous channel estimate signaled to the first communication device 100.

[0099] In step III in FIG. 12, the second communication device 300 calculates a first symbol constellation, also known as a baseline signal space constellation. The set of symbol points for all of the multiple radiation patterns is

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[0100] Optionally, the second communication device 300 may transmit the first symbol sequence S1 (set S2) directly to the first communication device 100, as illustrated by the dashed arrow extending from box III.

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[0101] In step IV of FIG. 12, the first symbol sequence

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[0102] In step V in FIG. 12, after calculating the set of complex weights, the second communication device 300 transmits to the first communication device 100 the complex weights for i=1, 2, . . . , 2 m The set of calculated complex weights {w i}.

[0103] In practice, it is desirable to have a low feedback signaling overhead. To make this possible, the feedback signaling can be compressed to reduce the overhead. In some embodiments, the feedback is formed and represented by a binary string containing only a few bits. In the simplest case, the second communication device 300 obtains one radiation pattern for each antenna element, and thus N antenna elements using RF chains. t If there are a total of m radiation patterns for a system with m antennas, the feedback overhead is mN tWe assume that the feedback from the second communication device 300 to the first communication device 100 is 2 bits, i.e., in the case of two transmit antennas each with two radiation patterns, only 2 bits of feedback are needed from the second communication device 300 to the first communication device 100 to configure the first communication device 100.

[0104] In step VI in FIG. 12, the first communication device 100 obtains a second symbol sequence based on the set of weights and the first symbol sequence received from the second communication device 300 .

[0105] In some embodiments, the first communication device 100 obtains the second symbol sequence by mapping the first symbol sequence to a set of weights to obtain the second symbol sequence. The mapping may be a linear mapping. One simple example of a linear mapping is to element-wise multiply the first symbol sequence with the weights to generate the second symbol sequence.

[0106] In some embodiments, after mapping the first symbol sequence to the set of weights, power control and phase shifting are performed to obtain the second symbol sequence.

[0107] In some embodiments, the second symbol sequence is one of M-PSK, e.g., BPSK and QPSK, or M-QAM, e.g., 16-QAM and 64QAM, where M is a positive integer. A set of weights may be calculated such that the symbols in the second symbol sequence form a legacy symbol sequence for transmission that is accessible to other legacy receivers of the second communication device 300. Another example is weights obtained such that the new symbol sequence has an enhanced shaping gain (which is known in coding theory and is achieved, e.g., by optimizing the position constellation points in the signal space or optimizing the probability distribution of the signal points). Weights may also be obtained to generate new symbol sequences to form multidimensional lattices with desired generator matrices with basic paralleles. It is possible to optimize the properties of the lattices using weights that make them suitable for specific channel conditions.

[0108] In step VII in FIG. 12, the first communication device 100 transmits to the second communication device 300 the set of information bits that have been mapped to the calculated second symbol sequence S2 from step VI.

[0109] In step VIII in Fig. 12, the second communication device 300 receives the set of information bits that have been mapped to the calculated second symbol sequence S2. The second communication device 100 then performs demodulation and decoding of the received information based on the second symbol sequence and the used bit-to-symbol mapping.

[0110] In embodiments, the first communications device 100 may nevertheless not receive the set of weights directly from the second communications device 300, but rather obtain the set of weights by other techniques.

[0111] In some embodiments, the first communication device 100 receives from the second communication device 300 a set of channel estimates 610a, 610b, ..., 610n corresponding to the optional transmissions in step II in Fig. 12. Each channel estimate corresponds to a radiation pattern 600i of the set of radiation patterns 600a, 600b, ..., 600n. The first communication device 100 further calculates a set of weights based on the channel estimate 610n of the set of channel estimates 610a, 610b, ..., 610n and the first symbol sequence.

[0112] In some embodiments, the first communication device 100 receives a set of reference signals associated with a set of radiation patterns from the second communication device 300 (not shown in FIG. 12) and determines a set of channel estimates 610a, 610b, ..., 610n based on the received set of reference signals. Each channel estimate corresponds to a radiation pattern of the set of radiation patterns. The first communication device 100 then calculates a set of weights based on a channel estimate of the set of channel estimates. This case therefore relates to the example when the second communication device 300 transmits reference signals on behalf of the first communication device 100 to estimate the wireless channel, as illustrated in FIG. 12. This is possible because the antenna elements are reciprocal with respect to transmission and reception of RF signals.

[0113] Furthermore, the first communications device 100 may also obtain the first symbol sequence by a number of different techniques.

[0114] In some embodiments, the first communication device 100 receives a set of channel estimates 610a, 610b, ..., 610n from the second communication device 300 (see step II in Fig. 12). Each channel estimate corresponds to a radiation pattern 600i of the set of radiation patterns 600a, 600b, ..., 600n. The first communication device 100 calculates a first symbol sequence based on a channel estimate 610n of the set of channel estimates 610a, 610b, ..., 610n.

[0115] In some embodiments, the first communication device 100 receives a set of reference signals associated with a set of radiation patterns from the second communication device 300 and determines a set of channel estimates based on the received set of reference signals. Each channel estimate corresponds to a radiation pattern of the set of radiation patterns. The first communication device 100 calculates a first symbol sequence based on a channel estimate of the set of channel estimates. This also relates to an example when the second communication device 300 transmits reference signals on behalf of the first communication device 100 to estimate the wireless channel. This is possible because the set of antenna elements is reciprocal for transmission and reception of RF signals.

[0116] In embodiments, the first communication device 100 receives the first symbol sequence directly from the second communication device 300 in control signaling, as illustrated by the dashed arrow in Box III in Fig. 12. The first symbol sequence may for example be selected from a set of pre-determined codebooks known to both the first communication device 100 and the second communication device 300. Thereby, only the codebook index needs to be sent by signaling, thus reducing the control signaling overhead.

[0117] Furthermore, a flowchart of the algorithm for computing the set of weights is shown in more detail in Figure 13. The algorithm uses a stochastic perturbation method for a given design metric.

[0118] In step I in FIG. 13, an initial first symbol array is formed for all of the multiple radiation patterns.

[0119] In step II in FIG. 13, an initial set of complex weights corresponding to all of the radiation patterns in the set of radiation patterns is set.

[0120] In step III in FIG. 13, the metric is calculated. The algorithm sets the design metric and takes as input the set

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[0121] A design metric is set in step IV and provided to step III. The design metric may include, for example, minimum pairwise distance, such as Euclidean distance, or any other relevant distance measure, such as chordal distance, Shannon capacity, symbol error rate, block error rate, finite length capacity, bit interleaving capacity, outage capacity, and shaping gain, that are typically used for non-coherent communication. Reliability as well as delay constraints may be used as design metric.

[0122] In step V in FIG. 13, the initial set of weights are perturbed. In one example, the weights are

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[0123] In step VI, a simple linear mapping employing element-wise multiplication is used to map the set

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[0124] In step VII, a metric is calculated. For illustrative purposes, consider the minimum pairwise Euclidean distance as the objective function. The objective function is:

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[0125] In step VIII, if the perturbation produces a larger minimum distance, i.e., d k >d k-1 If so, then the perturbation is accepted; otherwise, a new random perturbation is selected until the design metric is enhanced.

[0126] In step IX, the process continues until there is no significant change in the metrics or the total number of trials selected for optimization is exhausted, i.e., continue along the NO branch in Figure 13. Otherwise, the YES branch in Figure 13 is taken and step X is executed.

[0127] In step X, i=1,2,…,2 m The complex weight w i After finding the weights, the first communication device 100 feeds back these weights or a signal indicating these weights. The new symbol sequence in the second communication device 300 is the set

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[0128] Figure 14 illustrates two examples of the disclosed solutions for shaping symbol arrays. In these examples, there are four antenna elements whose PIN diodes can be switched on and off independently, i.e., m=4, where m is a factor of 2.m = 16 points. The first symbol constellation is

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[0129] 15 shows the distribution of the minimum pairing distance for a population of symbol sequences according to the conventional solution and the disclosed solution. In this example, there are four antenna elements whose diodes can be switched on and off independently, i.e., m=4, where m is a function of 2 m This results in a symbol constellation with =16 points. It is assumed that the wireless channel from each antenna element to the second communication device 300 follows Rayleigh fading with unit variance.

[0130] The top figure in Figure 15 is

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[0131] On the other hand, the lower figure in Figure 15

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[0132] FIG. 16 shows the symbol error rate (SER) versus signal-to-noise ratio (Es / No) for three different transmission schemes.

[0133] Scheme 1 is a baseline open-loop MBM according to the conventional solution, in which there are four antenna elements whose diodes can be switched on and off independently, i.e., m=4, where m is a function of 2 mThis results in a symbol constellation with m = 16 points. It is assumed that the channel from each antenna element to the receiver follows independent Rayleigh fading with unit variance with AWGN noise at the receiver. Scheme 2 is a disclosed closed-loop MBM according to an embodiment similar to that of Scheme 1, in which there are four antenna elements whose diodes can be switched on and off independently, i.e., m = 4, where m is a function of 2 m This results in a symbol constellation with 16 = 16 points, but the transmitter is able to configure the weights for each channel variation. We assume that the channel from each mirror to the receiver follows Rayleigh fading with unit variance. Scheme 3 is a conventional 16QAM modulation with AWGN and is considered the benchmark.

[0134] From Fig. 16, it can be concluded that the disclosed solution significantly improves the baseline MBM scheme, achieving power gains of tens of dB at low SER. Additionally, the disclosed solution operates in the vicinity of AWGN channels.

[0135] Furthermore, in the following disclosure, we consider the transmission of low density parity check (LDPC) coded bits using conventional solutions. In the following, the transmitter has four antenna elements that can independently switch PIN diodes on and off, i.e. m=4. This means that 2 m = 16 points. The symbol arrangement according to the conventional solution is

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[0136] To allow the transmission of bits, it is also necessary to design a bit-to-symbol mapping. One approach is to use a multiple perturbation method, whereby the design metric is to minimize the Hamming distance of the bit labels to their nearest neighbors. The perturbation may be achieved by starting with an initial random mapping and then performing random bit flips. Other methods of optimization may also be applied. Figure 17d shows an example of a result obtained by perturbation. It can be seen that the symbols are grouped so that they are placed in separable rows, and then the mapping may be written such that two bits are assigned to each row and two additional bits are assigned to distinguish the symbols in each row. That is, columns b0b1b2b3 are assigned such that b0b1 indicates one of the four rows and b2b3 determines one of the four symbol points in each row. It has also been observed that the symbol constellation obtained using this method gives some edge points. Rotating these edge points can provide improved performance by allowing better bit-to-symbol mappings to be found, as shown in Figures 18a and 18b.

[0137] Fig. 18b illustrates a second symbol constellation after applying the initial weights, and Fig. 18a shows the same constellation with rotated edge points. Fig. 18a shows a symbol constellation when two edge points are enclosed, in which the rotation angle of the corresponding symbol points can be calculated and the corresponding weights can be readjusted. It should be noted that the rotation does not change the transmission power.

[0138] FIG. 19 shows the bit error rate (BER) in dB as a function of SNR for four LDPC transmission code schemes, namely, the baseline open-loop MBM according to the conventional solution, the disclosed closed-loop MBM according to the embodiments, the disclosed closed-loop MBM with rotated edge points according to the embodiments, and the conventional solution using 16QAM with AWGN as a benchmark, when the code rate is half. Also, the Shannon limit is shown. From FIG. 19, it can be concluded that the disclosed solution significantly improves the baseline MBM scheme with a power gain of several dB, which allows significant energy savings. Alternatively, the solution may be used to extend coverage. Rotating the edge points can further improve performance, making the disclosed solution work almost the same as the solution for 16QAM transmission over AWGN channels.

[0139] One of the main results of the present invention is that by using the disclosed solution, it is possible to transform a fading channel into an AWGN channel. That is, it can be seen that the present invention effectively enables channel enhancement by using weights to remove randomness in the effective wireless channel, whereby fading is used for data transmission. The solution may therefore be seen as enabling symbol shaping that enables channel enhancement by controlling fading for data transmission while transforming the fading channel into an AWGN channel.

[0140] Furthermore, any of the methods according to the embodiments of the present invention may be implemented by a computer program having code means which, when executed by a processing means, causes the processing means to perform the steps of the method. The computer program is included in a computer readable medium of a computer program product. The computer readable medium may include essentially any memory, such as a Read-Only Memory (ROM), a Programmable Read-Only Memory (PROM), an Erasable PROM (EPROM), a flash memory, an Electrically Erasable PROM (EEPROM), or a hard disk drive.

[0141] According to embodiments, the present disclosure provides a chip, which may be used for a first communication device and / or a second communication device, including at least one communication interface, at least one processor, and at least one memory, where the communication interface, the processor, and the memory are interconnected using a circuit (or, in some cases, using a bus), and where the processor invokes instructions stored in the memory to perform methods according to embodiments of the present invention.

[0142] According to embodiments, the present disclosure provides a first communication device and / or a second communication device including a memory and a processor, the memory configured to store program instructions, and the processor configured to invoke the program instructions in the memory to implement functionality of the first communication device and / or the second communication device according to embodiments of the present invention.

[0143] According to embodiments, the present disclosure provides a non-volatile storage medium, which stores one or more program codes, such that when the first communication device and / or the second communication device execute the program codes, the first communication device and / or the second communication device executes steps of associated methods executed by the first communication device and / or the second communication device according to embodiments of the present invention.

[0144] Furthermore, those skilled in the art will appreciate that embodiments of the first communication device 100 and the second communication device 300 include necessary communication capabilities, e.g. in the form of functions, means, units, elements, etc., to perform the solution. Examples of other such means, units, elements, and functions are processors, memories, buffers, control logic, encoders, decoders, rate matchers, de-rate matchers, mapping units, multipliers, decision units, selection units, switches, interleavers, de-interleavers, modulators, demodulators, inputs, outputs, antennas, amplifiers, receiving units, transmitting units, DSPs, MSDs, TCM encoders, TCM decoders, power supply units, power feeders, communication interfaces, communication protocols, etc., together suitably arranged to perform the solution.

[0145] In particular, the one or more processors of the first communication device 100 and the second communication device 300 may include, for example, one or more instances of a central processing unit (CPU), processing unit, processing circuit, processor, application specific integrated circuit (ASIC), microprocessor, or other processing logic capable of interpreting and executing instructions. Thus, the term "processor" may refer to a processing circuit including, for example, multiple processing circuits, such as any, some, or all of those mentioned above. The processing circuit may further perform data processing functions for input, output, and processing of data, including device control functions, such as call processing control or user interface control, and data buffering functions.

[0146] Finally, it is to be understood that the present invention is not limited to the embodiments described above, but also relates to and incorporates all of the embodiments within the scope of the appended independent claims.

Claims

1. A communication system including a first communication device and a second communication device, The first communication device: a set of antenna elements configured to operate with a set of radiation patterns by independently controlling the on / off of the m PIN diodes; a processor; The second communication device: receiving a set of reference signals from the first communication device, the set of reference signals associated with the set of radiation patterns of the set of antenna elements of the first communication device; determining a set of channel estimates based on the set of received reference signals, each channel estimate corresponding to a radiation pattern in the set of radiation patterns; determining a first symbol sequence based on a channel estimate from the set of channel estimates; Transmitting the first symbol sequence to the first communication device; Calculate a set of weights based on the channel estimates in the set of channel estimates and the first symbol sequence, the set of weights being calculated for an i-th radiation pattern in the set of radiation patterns according to: (a) The weight of stage k is w i (k) When k=0, the initial weight w i (0) Set to 1, i = 1, 2, …, 2 m and (b) All weights w at stage k-1 i (k-1) is subjected to randomly selected perturbations, k is an integer greater than 1, (c) The minimum pairing Euclidean distance d between stage k and stage k-1, subject to the power constraint. k and d k-1 Each of the following is determined: (c-1)d k >d k-1 If it satisfies the above, accept the perturbation, increase the value of k by 1, and repeat (b) above. (c-2)d k >d k-1 If it does not satisfy the above, repeat (b) with a new randomly selected perturbation while keeping the value of k constant. (d) determining the weights of the final stage k obtained for all i as the set of weights; transmitting the set of weights to the first communication device; It is configured as follows: The processor of the first communications device: obtaining, from the second communication device, a first symbol sequence based on a radiation pattern of the set of radiation patterns; obtaining the set of weights associated with the first symbol sequence from the second communication device; obtaining a second symbol sequence based on the first symbol sequence and the set of weights; and controlling the set of antenna elements according to the radiation pattern to transmit a set of information bits that are mapped to the second symbol sequence. Communication systems.

2. 2. The communications system of claim 1, wherein each antenna element in the set of antenna elements is configured to operate in a plurality of radiation states, whereby the set of antenna elements operates in the set of radiation patterns.

3. 3. The communication system of claim 2, wherein the set of antenna elements is disposed within a range of a radiating element configured to radiate electromagnetic waves, the set of antenna elements being a set of radio frequency mirrors.

4. Obtaining the second sequence of symbols includes:

4. A communication system as claimed in claim 1, further comprising: mapping the first symbol sequence onto the set of weights to obtain the second symbol sequence.

5. Obtaining the second sequence of symbols includes:

5. The communication system of claim 4, further comprising performing power control and phase shifting after mapping the first symbol sequence to the set of weights to obtain the second symbol sequence.

6. 5. The communication system of claim 4, wherein the second symbol sequence is one of M-PSK or M-QAM.

7. 1. A method implemented by a communication system including a first communication device and a second communication device, comprising: The first communication device transmitting a set of reference signals, the set of reference signals being associated with a set of radiation patterns of a set of antenna elements of the first communication device; by the second communication device determining a set of channel estimates based on the set of received reference signals, each channel estimate corresponding to a radiation pattern in the set of radiation patterns; determining a first symbol sequence based on a channel estimate from the set of channel estimates; transmitting the first symbol sequence to the first communication device; calculating a set of weights based on the channel estimate of the set of channel estimates and the first symbol sequence, the set of weights being calculated for an i-th radiation pattern of the set of radiation patterns according to: (a) The weight of stage k is w i (k) When k=0, the initial weight w i (0) Set to 1, i = 1, 2, …, 2 m and (b) All weights w at stage k-1 i (k-1) is subjected to randomly selected perturbations, k is an integer greater than 1, (c) The minimum pairing Euclidean distance d between stage k and stage k-1, subject to the power constraint. k and d k-1 Each of the following is determined: (c-1)d k >d k-1 If it satisfies the above, accept the perturbation, increase the value of k by 1, and repeat (b) above. (c-2)d k >d k-1 If it does not satisfy the above, repeat (b) with a new randomly selected perturbation while keeping the value of k constant. (d) determining the weights of the last stage k obtained for all i as the set of weights; transmitting the set of weights to the first communication device; The first communication device obtaining, from the second communication device, a first symbol sequence based on a radiation pattern of the set of radiation patterns; obtaining the set of weights associated with the first symbol sequence from the second communication device; obtaining a second symbol sequence based on the first symbol sequence and the set of weights; controlling the set of antenna elements according to the radiation pattern to transmit a set of information bits that are mapped to the second symbol sequence; The method includes:

8. A computer program having a program code for performing the method according to claim 7, when the computer program is executed in a first communication device and a second communication device comprised in a communication system.

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