Method of beam management in digitally controllable scatterer (DCS), assisted communication system

Abstract

A method of beam management in a digitally controllable scatterer (DCS) assisted communication system including a base station (BS) for transmitting one or more first signals via one or more first beams and transmitting one or more second signals via one or more second beams towards one or more DCSs. Moreover, each first beam including a different index, a different direction, and a different coverage area depending on an index of the first beam. Each of the DCSs is configured for generating third signals by scattering one or more of the second signals. Each third signal is a coded version of the impinging second signals encoded by the DCS with a unique code and transmitted via a third beam with a coverage area overlapping with a coverage area of the one or more first beams. The method provides an improved beam pairing process with less overhead for beam selection.

Description

[0001] METHOD OF BEAM MANAGEMENT IN DIGITALLY CONTROLLABLE SCATTERER (DCS), ASSISTED COMMUNICATION SYSTEM

[0002] TECHNICAL FIELD

[0003] The present disclosure relates generally to the field of wireless communication systems and, more specifically, to a method of beam management in digitally controllable scatterer (DCS) assisted communication system, and a DCS assisted communication system.

[0004] BACKGROUND

[0005] Currently, in a cellular network, high frequencies, such as millimeter waves or terahertz waves, are getting more consideration for different types of transmitters as well as receivers because such frequencies offer much more bandwidth. However, higher carrier frequency makes the propagation conditions harsher than at lower frequencies, which are used for wireless applications, especially in terms of robustness. Furthermore, there exists an increased path loss and penetration loss, which limit the coverage of signals transmitted by the transmitters at high frequencies, and the signals may easily be blocked by many common materials, which is not desirable. The blockage problem similarly occurs in conventional cellular networks operated at lower frequencies. As a result, the signals received by the receivers lead to transmission errors due to the blockage as well as due to low signal-to-interference-plus-noise ratio (SINR).

[0006] Currently, certain attempts have been made to overcome the problems related to signal blockage, increased path loss and penetration loss, such as by using highly directional antennas in a base station (BS) and a user equipment (UE) to achieve a sufficient link budget in wide area networks. The consequence is the need for precise alignment of transmitter beams and receiver beams, which may not only increase the latency of establishing a link, but also consumes a lot of time and frequency resources. In addition, feasibility remains an issue with respect to beam alignment because it requires precise and accurate alignment of the beams, which can be challenging in certain conditions, such as difficult atmospheric conditions. Therefore, there exists a technical problem of how to manage beam selection process in the communication systems, with reduced cost, speed of convergence, and less overhead.

[0007] Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks associated with conventional communication systems. SUMMARY

[0008] The present disclosure provides a method of beam management in a digitally controllable scatterer (DCS) assisted communication system and a DCS assisted communication system. The present disclosure provides a solution to the existing problem of beam selection, with less overhead. An aim of the present disclosure is to provide a solution that overcomes at least partially the problems encountered in the prior art and provides an improved method of beam management in a DCS, assisted communication system, and an improved DCS assisted communication system.

[0009] One or more objectives of the present disclosure are achieved by the solutions provided in the enclosed independent claims. Advantageous implementations of the present disclosure are further defined in the dependent claims.

[0010] In one aspect, the present disclosure provides a method of beam management in a digitally controllable scatterer (DCS) assisted communication system, comprising: a base station (BS) transmitting one or more first signals via one or more first beams within a set of first beams, wherein each first beam has a different index, a different direction and a different coverage area depending on an index of the first beam, the BS transmitting one or more second signals via one or more second beams towards one or more digitally controllable scatterers (DCSs), wherein each second beam is directed towards a different DCS, and each second signal is a function of the one or more first signals, and each of the DCSs, generating third signals by scattering one or more of the second signals impinging on the DCS, wherein each third signal is a coded version of the impinging second signals encoded by the DCS with a unique code and transmitted via a third beam with a coverage area overlapping with a coverage area of the one or more first beams that transmit the one or more first signals comprised as a part of the function in the impinging second signals.

[0011] The method is beneficial to provide an improved beam selection process with less overhead. Moreover, any region targeted by the one or more first beams can be further provided with the one or more third beams, which is beneficial to improve the amount of information that can be measured with the training signal of the BS. Furthermore, the BS can obtain a more accurate location and beam information, which can be applied to subsequent algorithm design, such as to estimate an improved angle of arrival (AoA) and an angle of departure (AoD) of a line of sight (LoS) path between the BS and each of the UEs, with less overhead (or training time). Moreover, as the one or more third signals are the encoded signals, thus each third signal can be easily separated from each other and from the one or more first signals.

[0012] In a further implementation form, each of the UEs, in response to receiving one or more first signals via one or more first beams and one or more third signals via one or more third beams: obtaining performance metrics for the one or more first beams and the one or more third beams based on the received signals, selecting a set of preferred first beams and / or a set of preferred third beams, based on the performance metrics, and reporting to the BS the feedback information comprising an information about the set of preferred first beams and / or the set of preferred third beams, and the BS selecting a preferred first beam and / or a preferred third beam from the set of preferred first beams and / or the set of preferred third beams for each of the UEs based on the feedback information reported by said UE.

[0013] The set of preferred first beams and / or the set of preferred third beams are selected to improve the amount of information to be measured by the BS.

[0014] In a further implementation form, the generating of each of the one or more narrow beams by the BS comprises: the BS generating a sub-beam of the preferred first beam, the sub-beam having a coverage area that corresponds to the coverage area of the preferred third beam, or the BS generating one of the second beams towards one of the DCSs and the said DCS generating a narrow beam that corresponds to the preferred third beam.

[0015] In this implementation, the BS can generate the first beam (e.g., a wide beam) and then use the feedback information for the beam selection to generate further beam (e.g., a narrow beam) towards the target area, such as a UE.

[0016] In a further implementation form, the method further comprising the BS providing each of the DCSs with an information about the indexes or the coverage areas of the one or more first beams.

[0017] In this implementation, each of the DCSs is aware of the coverage areas of the one or more first beams. In a further implementation form, the generating of third signals by scattering one or more of the second signals impinging on each of the DCSs comprises the DCS applying scattering patterns to its controllable scattering elements, wherein the scattering patterns are based on the indexes or the coverage areas of the one or more first beams that transmit the one or more first signals which are comprised as a part of the function in the impinging second signals.

[0018] The one or more third signals are generated to cover either the same region as the one or more first signals or a subregion of the one or more first signals transmitted by the BS.

[0019] In a further implementation form, the unique codes for encoding the second signals into the third signals comprise frequency modulation codes or phase modulation codes.

[0020] In a further implementation form, the method comprising each of the UEs obtaining an information on the unique codes for decoding the third signals via a downlink control information from the BS and / or using a pre-defined protocol.

[0021] In this implementation, each of the UEs can obtain channel estimation with the DCS or without the DCS.

[0022] In a further implementation form, the method further comprising each of the UEs decoding the third signals and the corresponding one or more first signals received by the UE using the information on the unique codes.

[0023] By virtue of decoding the third signals and the corresponding one or more first signals, each UE from the one or more UEs can obtain the channel estimation of each beam with the DCS and without the DCS.

[0024] In a further implementation form, the obtaining of performance metrics by each of the UEs comprises the UE measuring a signal strength and / or a signal to noise ratio for each of the received signals.

[0025] By virtue of measuring the signal strength and / or a signal to noise ratio for each of the received signals, each of the UEs can determine the quality metric of the received signals, which can be used to provide the feedback information to the BS, such as to improve the efficiency of the BS.

[0026] In a further implementation form, the method further comprising, by each of the UEs: selecting a UE preferred first beam among the set of preferred first beams and a UE preferred third beam among the set of preferred third beams based on the performance metrics of the preferred first beams and the preferred third beams, setting a status flag to indicate if the performance metric of the UE preferred first beam exceeds that of the UE preferred third beam by a pre-defined threshold value, and adding the status flag into the feedback information.

[0027] In this implementation, the status flag is used to indicate whether the UE preferred first beam, or the UE preferred third beam is the dominant one.

[0028] In a further implementation form, the method further comprising each of the UEs adding the performance metrics of the preferred first beams and the preferred third beams into the feedback information.

[0029] The feedback information provides information related to both the first beams and the third beams that are used for serving each of the UEs.

[0030] In another aspect, the present disclosure provides a Digitally Controllable Scatterer (DCS), assisted communication system, comprising: a base station (BS), configured for transmitting one or more first signals via one or more first beams within a set of first beams, wherein each first beam has a different index, a different direction and a different coverage area depending on an index of the first beam, and transmitting one or more second signals via one or more second beams towards one or more Digitally Controllable Scatterers (DCSs), wherein each second beam is directed towards a different DCS, and each second signal is a function of the one or more first signals, wherein each of the DCSs is configured for generating third signals by scattering one or more of the second signals impinging on the DCS, wherein each third signal is a coded version of the impinging second signals encoded by the DCS with a unique code and transmitted via a third beam with a coverage area overlapping with a coverage area of the one or more first beams that transmit the one or more first signals comprised as a part of the function in the impinging second signals. The disclosed DCS assisted communication system achieves all the advantages and technical features of the method of the present disclosure.

[0031] It is to be appreciated that all the aforementioned implementation forms can be combined. It is to be noted that all devices, elements, circuitry, units, and means described in the present application could be implemented in the software or hardware elements or any kind of combination thereof. All steps which are performed by the various entities described in the present application, as well as the functionalities described to be performed by the various entities, are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. Even if, in the following description of specific embodiments, a specific functionality or step to be performed by external entities is not reflected in the description of a specific detailed element of that entity that performs that specific step or functionality, it should be clear for a skilled person that these methods and functionalities can be implemented in respective software or hardware elements, or any kind of combination thereof. It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.

[0032] Additional aspects, advantages, features, and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative implementations construed in conjunction with the appended claims that follow.

[0033] BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those skilled in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.

[0035] Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein: FIG. 1 is a flow chart of a method of beam management in a digitally controllable scatterer (DCS) assisted communication system, in accordance with an embodiment of the present disclosure;

[0036] FIG. 2 is a diagram that depicts a digitally controllable scatterer (DCS) assisted communication system, in accordance with an embodiment of the present disclosure;

[0037] FIG. 3 is a flowchart that depicts a beam selection process in a digitally controllable scatterer (DCS) assisted communication system, in accordance with an embodiment of the present disclosure;

[0038] FIG. 4A and 4B are different diagrams that depict a beam generation process in a digitally controllable scatterer (DCS) assisted communication system, in accordance with different embodiments of the present disclosure;

[0039] FIG. 5 is a diagram that depicts a digitally controllable scatterer (DCS) applying scattering patterns to controllable scattering elements, in accordance with an embodiment of the present disclosure;

[0040] FIGs. 6A and 6B are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam selection with DCS in line of sight (LOS) condition, in accordance with different embodiments of the present disclosure;

[0041] FIGs. 7A and 7B are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam selection with DCS in Non-line of sight (NLOS) condition, in accordance with different embodiments of the present disclosure;

[0042] FIGs. 8A, 8B and 8C are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam mapping after receiving beam information in a line of sight (LOS) condition, in accordance with different embodiments of the present disclosure;

[0043] FIGs. 9A and 9B are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam mapping after receiving beam information in Non-line of sight (NLOS) condition, in accordance with different embodiments of the present disclosure;

[0044] FIGs. 10A, 10B, IOC, and 10D are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam selection with a DCS in multipleusers scenario, in accordance with different embodiments of the present disclosure;

[0045] FIGs. 11 A, 1 IB, 11C, and 1 ID are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam selection with multiple DCSs in multiple-users scenario, in accordance with different embodiments of the present disclosure; FIGs. 12A and 12B are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam selection with multiple first beams, in accordance with different embodiments of the present disclosure;

[0046] FIGs. 13 A and 13B are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam selection with multiple first beams and multiple DCSs, in accordance with different embodiments of the present disclosure; and

[0047] FIGs. 14A to 14E are illustrations of different exemplary configurations of scattering surfaces of a digitally controllable scatterer (DCS), in accordance with different embodiments of the present disclosure.

[0048] In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the nonunderlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.

[0049] DETAILED DESCRIPTION OF EMBODIMENTS

[0050] The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practising the present disclosure are also possible.

[0051] FIG. 1 is a flow chart of a method of beam management in a digitally controllable scatterer (DCS), assisted communication system, in accordance with an embodiment of the present disclosure. With reference to FIG. 1 A, there is shown a flow chart of a method 100. The method 100 includes steps 102-to-106. The method 100 of beam management is used in a digitally controllable scatterer (DCS) assisted communication system.

[0052] At step 102, the method 100 comprises, transmitting, by a base station (BS), one or more first signals via one or more first beams within a set of first beams. Furthermore, each first beam includes a different index, a different direction, and a different coverage area depending on an index of the first beam. Firstly, the BS is configured to generate the one or more first signals, and then transmit the one or more signals via the one or more first beams and within the set of first beams. In addition, the index of each first beam is different from the one or more first beams within the set of first beams, as further shown and described in FIGs. 2, 4A, and 4B. In an implementation, the BS is configured to transmit the one or more first signals via the one or more first beams to one or more user equipment (UEs). Furthermore, each first signal from the one or more first signals is transmitted in the different direction based on the index of the corresponding first beam, such as to cover the different coverage areas depending on the index of the first beam that is used for beam sweeping.

[0053] At step 104, the method 100 comprises, transmitting, by the BS, one or more second signals via one or more second beams towards one or more digitally controllable scatterers (DCSs). Furthermore, each second beam is directed towards a different DCS, and each second signal is a function of the one or more first signals. Firstly, the BS is configured to generate the one or more second signals and then transmit the one or more second signals via the one or more second beams towards the one or more DCSs, as further shown and described in FIGs. 2, 4A, and 4B. Furthermore, each second signal from the one or more second signals is directed and transmitted towards the different DCS from the one or more DCSs based on the direction as well as possible location of the one or more DCSs. In addition, each second signal is a function of the one or more first signals, due to which two different types of signals, such as the one or more first signals and the one or more second signals, are transmitted simultaneously by the BS. Furthermore, the one or more first signals are transmitted without the DCS for beam sweeping, and the one or more second beams are directed to focus on the one or more DCSs during the search process, as shown in FIGs. 2, 4 A, and 4B. Furthermore, the one or more first beams and the one or more second beams are simultaneously used for transmitting the corresponding signals while having different beam directions. In accordance with an embodiment, the BS is configured for selecting one of the DCSs for generating one of the second beams towards said DCS based on pre-defined locations of the DCSs and / or the indexes or the coverage areas of the corresponding one or more first beams. In an example, the BS is configured to select a first DCS from the one or more DCSs and generates the one of the second beams toward the first DCS. In another example, the BS selects a second DCS from the one or more DCSs and generates one of the second beams (i.e., different from previous second beams) towards another DCS (e.g., a second DCS, a third DCS, and the like). Moreover, the BS is configured to generate the second beams based on different types of information available for the BS, including but not limited to channel state information (channel estimates), a feedback information from one or more UEs, a feedback information from a third party, pre-defined settings, etc. In an implementation, the BS is configured to generate the second beams based on the pre-defined locations of each DCS from the one or more DCSs, for example, in a different direction based on the pre-defined location of the corresponding DCS. In addition, for a given DCS the second beam for that DCS is focused towards it. The BS is also configured to generate the one of the second beams based on the indexes or the coverage areas of the corresponding one or more first beams.

[0054] In accordance with an embodiment, the method 100 further comprises, providing, by the BS, each of the DCSs with an information about the indexes or the coverage areas of the one or more first beams. As a result, each DCS of the DCSs is aware of the coverage areas of the one or more first beams. In an implementation, each DCS is informed by the BS about the indexes of the one or more first beams. In another implementation, each DCS is informed by the BS about the coverage areas of the one or more first beams.

[0055] In accordance with an embodiment, the one or more DCSs are configured for receiving from the BS a set of the unique codes for encoding the one or more second signals into the one or more third signals, and / or the one or more DCSs are configured for computing the set of the unique codes for encoding the one or more second signals into the one or more third signals based on the indexes or the coverage areas of the one or more first beams that transmit the one or more first signals, which are comprised as a part of the function in the impinging second signals. In an implementation, the one or more DCSs are configured for receiving from the BS the set of the unique codes for encoding the one or more second signals into the one or more third signals. In another implementation, the one or more DCSs are configured for computing the set of the unique codes for encoding the one or more second signals into the one or more third signals. Moreover, the one or more second signals are encoded into the one or more third signals based on the indexes or the coverage areas of the one or more first beams that transmit the one or more first signals. For example, the one or more DCSs are configured to receive and select J+ 1 unique codes (or codewords) CDCS. from the BS and assign for each beam one of the unique codes, such asj = 1, . . ., J. In an example, the value of J and the unique codes CDCS. are pre-defined for each DCS from the one or more DCSs. Moreover, the unique codes are only applied to the second signals by the one or more DCSs. In such embodiment, the unique codes for encoding the one or more second signals into the one or more third signals include frequency modulation codes or phase modulation codes. In other words, each DCS is configured to modulate the one or more second signals. In an example, each of the DCSs is configured to use the frequency modulation codes for modulating the one or more second signals, for example, by applying frequency modulation (or DCS frequency modulation) on the one or more second signals. In another example, each of the DCSs is configured to use the phase modulation codes for modulating the one or more second signals, for example, by applying phase modulation (or DCS phase modulation) on the one or more second signals.

[0056] At step 106, the method 100 comprises, generating, by each of the DCSs, third signals by scattering one or more of the second signals impinging on the DCS. Moreover, each third signal is a coded version of the impinging second signals encoded by the DCS with a unique code from the set of the unique codes. For example, a DCS is configured to use the unique code to encode the one or more of the second signals that impinge on the corresponding DCS and generates the one or more third signals, which may also be referred to as coded signals or DCS coded signals. As a result, each third signal generated by each of the DCSs is the coded version of the impinging second signals. In an example, a third signal generated by a DCS is different from another third signal that is generated by another DCS. The method 100 further comprises, transmitting, by each of the DCSs, the one or more third signals via one or more third beams with a coverage area overlapping with a coverage area of the one or more first beams that transmit the one or more first signals comprised as a part of the function in the impinging second signals. In an implementation, each of the DCSs is configured to transmit the one or more third signals via the one or more third beams to the one or more UEs, such as the one or more third beams of the DCS covers a sub-region or the same region of the one or more first beams (e.g., targeted to same UE). Moreover, as the one or more third signals are the encoded signals, thus each third signal can be easily separated from the one or more first signals. In other words, the set of the unique codes is beneficial for separability within the one or more third signals and the one or more first signals.

[0057] In an implementation, the BS includes a predefined set of the first beams B. In an example, a set Brstcorresponds to a set of first beam that is selected through the beam sweeping process among the beam set of the first beams . Moreover, a set ®jeco„dcorresponds to a set of second beams constructed by the BS, which focus on the set of the DCS {DCS}. In addition, the one or more second signals transmitted on the one or more second beams are a function of the one or more first signals transmitted on the one or more first beams when multiple first beams are selected. As a result, the third beams, such as beams 'B ijj are generated due to DCS scattering of the second beam.

[0058] In accordance with an embodiment, each of the DCSs includes subsets of controllable scattering elements. Moreover, in this embodiment, each of the DCSs is configured for controlling phases of the scattering elements in each of the subsets to generate the third signals transmitted via the third beams. In an implementation, the subsets of controllable scattering elements in each of the DCSs are divided into J subsets by creating J subpanels. Moreover, by controlling the phases of the controllable scattering elements in each subset, N number of third signals can be generated by each of the DCSs, such as each third signal can focus on a different direction (e.g., on a different UE that can be located in different directions). In such an embodiment, the DCS is configured for applying scattering patterns to its controllable scattering elements. Moreover, the scattering patterns are based on the indexes or the coverage areas of the one or more first beams that transmit the one or more first signals, which are comprised as a part of the function in the impinging second signals. In other words, each of the DCSs is configured to apply the scattering patterns to corresponding controllable scattering elements to generate the one or more third signals. In an implementation, the one or more first signals and the one or more third signals (or a set of coded signals) are generated at the same time by the BS and each DCS, respectively. The one or more third signals are generated to cover either the same region as the one or more first signals or a subregion of the one or more first signals transmitted by the BS.

[0059] In an implementation, a scattering pattern isused to denote a scattering pattern matrix of each of the DCSs beam j related to a first beam i. In an example, the scattering pattern is based on the indexes of the one or more first beams through which the one or more first signals are transmitted. In another example, the scattering pattern F isbased on the coverage areas of the one or more first beams. Moreover, in a phase shifter-based implementation, the scattering pattern is afunction of scattering phases DlCSj applied by the subsets of controllable scattering elements of the each of the DCSs. In addition, based on the index of the first beam, the scattering pattern F(4>pCS) of j-th DCS subset can be configured online or offline. In an implementation scenario, the scattering pattern F °f j-th DCS subpanel is computed offline. Moreover, each of the DCSs subpanels can obtain the scattering pattern F ( pCs;based on the index of the first beam or corresponding coverage area. In another implementation scenario, the scattering pattern °f J "th DCS subpanel is computed online. Moreover, each of the DCSs can calculate online the scattering pattern F (orselect the precalculated one) based on the location of the BS and the possible location of the UE (if available), such as the location of the UE is known at the previous time slots. In an example, the scattering pattern F isprovided by any other device, such as provided by a controller or a processor. Furthermore, the scattering pattern F is updated synchronously with the first beam sweeping, where the superscript i is the first beam index.

[0060] In accordance with an embodiment, each of the UEs, in response to receiving one or more first signals via one or more first beams and one or more third signals via one or more third beams, obtaining performance metrics for the one or more first beams and the one or more third beams based on the received signals. Firstly, each of the UEs is configured for reception during the transmission of the one or more first signals and the one or more third signals. Thereafter, each of the UEs is configured to obtain the performance metrics for the one or more first beams based on the received one or more first signals and also for the one or more third beams (i.e., coded beams) based on the received one or more third signals. Furthermore, each of the UEs is configured to select a set of preferred first beams and / or a set of preferred third beams based on the performance metrics. In an implementation, each of the UEs is configured to select the set of preferred first beams based on the performance metrics. In another implementation, each of the UEs is configured to select the set of preferred third beams based on the performance metrics. In yet another implementation, each of the UEs is configured to select the set of preferred first beams and the set of preferred third beams based on the performance metrics. Thereafter, each of the UEs is configured for reporting to the BS the feedback information, including an information about the set of preferred first beams and / or the set of preferred third beams. In an example, the feedback information includes details related to any region targeted by a preferred first beam. In an implementation, the feedback information includes the information about the set of preferred first beams. In another implementation, the feedback information includes the information about the set of preferred third beams. In another implementation, the feedback information includes the information about the set of preferred first beams and the set of preferred third beams. In an implementation, each of the UEs is configured to obtain performance metrics for the one or more first beams and the one or more third beams. For example, each of the fc=l,2,. . ,,K UEs is configured to obtain the RSRPQk, RSRPCSi k,..., of each z-th first beam, such as the RSRP is signal strength or power received from a single reference signal. After that, each of the UEs is configured to compare the performance metrics of the one or more first beams and the one or more third beams that it has measured. Furthermore, each of the UEs is configured to obtain an index of its preferred (e.g., strongest) first beam, such as maxi = i* and its corresponding third beam index, such as maxj = j* .

[0061] In such embodiment, the obtaining of performance metrics by each of the UEs includes the UE measuring a signal strength and / or a signal to noise ratio for each of the received signals. In an implementation, each of the UEs is configured to measure the signal strength for each of the one or more first signals and the one or more third signals. In another implementation, each of the UEs is configured to measure the signal to noise ratio for each of the one or more first signals and the one or more third signals. In yet another implementation, each of the UEs is configured to measure the signal strength and the signal to noise ratio for each of the one or more first signals and the one or more third signals. By virtue of measuring the signal strength and / or a signal to noise ratio for each of the received signals, each of the UEs can obtain the quality of the received signals so as to compare them and decide which has better quality, which can be used to provide the feedback information to the BS, such as to improve the efficiency of the BS. For example, due to the presence of an obstacle, there exists the non-line of sight (NLOS) condition on a first beam, and then the signal strength and / or the signal to noise ratio for each of the received signals can be altered, which affects the performance metrics. Therefore, in such cases, the BS is configured to receive the feedback information from the corresponding UE, such as to improve the amount of information that can be measured with a training signal of the BS 202.

[0062] In such embodiments, each of the UEs is configured for selecting a UE preferred first beam among the set of preferred first beams and a UE preferred third beam among the set of preferred third beams based on the performance metrics of the preferred first beams and the preferred third beams. Thereafter, each of the UEs is configured for setting a status flag to indicate if the performance metric of the UE preferred first beam exceeds that of the UE preferred third beam by a pre-defined threshold value. Furthermore, each of the UEs is configured for adding the status flag into the feedback information. In an example, a preferred (e.g., a maximal) first beam index maxi is determined, such as with maxi = i* , where i* is the preferred first beam index i among . In another example, a preferred (e.g., a maximal coded) third beam index maxj with the status flag is determined, such as with maxj = j*, where j* is the preferred third beam index j among \ metricDlCS.k1 . Moreover, the status flag is set to indicate whether the UE preferred first beam, or the UE preferred third beam is the dominant one. In an implementation, each of the UEs is configured to define a parameter IsUseNonDCS for setting the status flag and consider Athreas a threshold. Optionally, due to the existence of a line of sight (LoS) link between the BS and the UE, If RSRPQK— RSRPCS .t k>thre, then the channel without the DCS Ho / kis dominant, and set the status flag IsUseNonDCS = 1. Therefore, the UE preferred third beam (e.g., strongest coded beam) from the third beams reflected by the DCS HQCS^Kis used by the UE to identify an improved beam information of the UE. In an implementation, each of the UEs is configured for adding the performance metrics of the preferred first beams and the preferred third beams into the feedback information. Therefore, the feedback information is received by the BS to select the preferred first beams and the preferred third beams based on the performance metrics. In other words, after receiving the beam information, the BS selects a preferred first beam and a preferred third beam from the reported set of first beams and a set of third beams for each of the UEs. Therefore, the feedback information provides information related to both the first beams and the third beams that are used for serving each of the UEs.

[0063] In accordance with an embodiment, each of the UEs is configured for obtaining an information on the unique codes for decoding the one or more first signals and / or the one or more third signals via a downlink control information from the BS and / or using a pre-defined protocol. In an implementation, the one or more UEs are configured for reception during the transmission of the one or more first signals and the one or more third signals. In an example, each of the UEs is configured to obtain the information on the unique codes by the downlink control information from the BS, such as for decoding the one of more first signals and the one or more third signals, with improved efficiency. In another example, each of the UEs is configured to obtain the information on the unique codes for decoding the one of more first signals and the one or more third signals by using the pre-defined protocol, with reduced cost. In yet another example, each of the UEs is configured to obtain the information on the unique codes for decoding the one of more first signals and the one or more third signals via the downlink control information from the BS and by using the pre-defined protocol. Therefore, each of the UEs can obtain channel estimate with the DCS and / or without the DCS. For example, each of the UEs can obtain each channel estimate with or without the DCS H H . . . , . . . , received signal processing based on the selected modulation for separability. In an example, is used to denote the channel estimate without the DCS measured at the UE k when the first beam i is used at the BS. In another example, HQCS.kis used to denote the channel estimate for the DCS channel via beam j measured at UE k when the first beam i is used at the BS.

[0064] In accordance with an embodiment, each of the UEs is configured for decoding the one or more third signals and the corresponding one or more first signals received by the UE using the information on the unique codes. In an implementation, each subpanel of the DCS applies the unique codes, such as codewords CDCS. in the one or more third signals. By virtue of decoding the third signals and the corresponding one or more first signals, each UE from the one or more UEs can obtain the channel estimation of each beam with the DCS and without the DCS. Moreover, each UE from the one or more UEs is configured to perform the beam selection or beam set selection (or beam comparison) by using the channel estimations and / or the calculated performance metrics of the one or more first beams and the one or more third beams and provides the feedback information to inform the BS about the beam selection of beam set selection.

[0065] In accordance with an embodiment, the BS is configured for receiving the feedback information from one or more UEs about one or more of the first beams and / or one or more of the one or more third beams. In an example, the BS is configured to use the feedback information to determine the corresponding beam weight by lookup a mapping table. Moreover, the feedback information provides information of the one or more of the first beams and / or one or more of the third beams that are used for serving each UE from the one or more UEs. In an implementation, the BS is configured to receive the feedback information from the one or more UEs, about one or more of the first beams, which is used to determine the beam weight of the one or more of the first beams. In another implementation, the BS is configured to receive the feedback information from the one or more UEs, about the one or more third beams, which is used to determine the beam weight of the one or more third beams. In yet another implementation, the BS is configured to receive the feedback information from the one or more UEs, about the one or more first beams and the one or more thirds beams, which is used to determine the beam weight of the one or more first beams and also of the one or more third beams. Moreover, after receiving the feedback information, the BS is configured to select the preferred (i.e., a finest or a best) first beam and the preferred third beam (i.e., coded beam) from the reported set of first beams and set of third beams for each of the UEs.

[0066] In an implementation, the BS is configured to select a preferred first beam and / or a preferred third beam from the set of preferred first beams and / or the set of preferred third beams for each of the UEs based on the feedback information reported by said UE. In an implementation, the BS is configured to select a preferred first beam from the set of preferred first beams for each of the UEs based on the feedback information reported by said UE. In another implementation, the BS is configured to select a preferred third beam from the set of preferred third beams for each of the UEs based on the feedback information reported by said UE. In yet another implementation, the BS is configured to select the preferred first beam and the preferred third beam from the set of preferred first beams and the set of preferred third beams for each of the UEs based on the feedback information reported by the said UE. Furthermore, the feedback information is computed by each of the one or more UEs based on the one or more first signals and / or the one or more third signals received by the UE. In an implementation, each UE from the one or more UEs is configured to compute the feedback information based on the one or more first signals received by the UE. In another implementation, each UE from the one or more UEs is configured to compute the feedback information based on the one or more third signals received by the UE. In yet another implementation, each UE from the one or more UEs is configured to compute the feedback information based on the one or more first signals and based on the one or more third signals received by the UE.

[0067] In an embodiment, the method 100 comprises, generating, by the BS, one or more narrow beams for communicating with the one or more UEs, such as each narrow beam includes either a subbeam of one of the first beams generated by the BS or a beam generated by one of the DCSs that corresponds to one of the third beams, and each narrow beam is focused on one of the UEs based on the feedback information. In other words, the BS is configured to generate the one or more narrow beams for communicating with the one or more UEs. In an implementation, each narrow beam includes the sub-beam of one of the first beams generated by the BS. In an example, the BS is configured to combine an information about the selected first beam and one of the third beams to generate the sub-beam of one of the first beams. In another implementation, each narrow beam includes the beam generated by one of the DCSs that corresponds to one of the third beams. Moreover, each narrow beam can be focused towards one of the UEs based on the feedback information, for example, in a particular direction. In such embodiment, a narrow beam is focused on one of the UEs based on the selection of the preferred first beam and / or the preferred third beam for said UE by the BS. In addition, each narrow beam can be focused on one of the UEs or each narrow beam can be focused on a different UE. In an example, the preferred beams are selected from the set of preferred beams. In an implementation, each of the narrow beams is focused on one of the UEs based on the selection of the preferred first beam for the said UE by the BS. In another implementation, each of the narrow beams is focused on one of the UEs based on the selection of the preferred third beam for said UE by the BS. In yet another implementation, each of the narrow beams is focused on one of the UEs based on the selection of the preferred first beam, and the preferred third beam for said UE by the BS. Moreover, each of the UEs reports different beam information to the BS in the different transmission processes. For example, in a cell search process, the preferred first beam with index maxi, the preferred third beam (or a maximal coded beam) with index maxj and the status flag (e.g., IsUseNonDCS) are fed back to the BS by each of the UEs. In an example, each of the UEs can additionally report the set of preferred first beams index, the set of preferred third beams index, the metric^k, metricDlCS.k, and the status flag (e.g., IsUseNonDCS) to the BS.

[0068] In accordance with an embodiment, the BS is further configured for generating the sub-beam of the preferred first beam, the sub-beam including a coverage area that corresponds to the coverage area of the preferred third beam, or the BS generating one of the second beams towards one of the DCSs and the said DCS generating a narrow beam that corresponds to the preferred third beam. In an implementation, the BS is configured to generate the sub-beam of the preferred first beam, such as the sub-beam includes the coverage area that corresponds to the coverage area of the preferred third beam. In an example, the preferred first beam is selected from the set of preferred beams. Moreover, the coverage area of the sub-beam is directed towards the UE. In another implementation, the BS is configured to generate the one of the second beams towards one of the DCSs, and the said DCS is configured to generate the narrow beam that corresponds to the preferred third beam.

[0069] In accordance with an embodiment, the BS is configured for generating the sub-beam of the preferred first beam if the performance metric of the preferred first beam exceeds that of the preferred third beam by a pre-defined threshold. In an implementation, the UE reports the preferred first beam index (e.g., maxi = i*), the preferred third beam (or DCS coded beam) index (e.g., maxj = j*), and the status flag (e.g., IsUseNonDCS) to the BS. Thereafter, the BS is configured to determine if the performance metric of the preferred first beam exceeds that of the preferred third beam by the pre-defined threshold and then generate the sub-beam of the preferred first beam. In other words, the BS can obtain an improved information and apply subsequent process or algorithm design to the received information to generate the sub-beam within the preferred first beam directly to the UE, as further shown and described in FIGs. 2, 4, and 5. In an example, the status flag (e.g., IsUseNonDCS =1) indicates that the first beam without DCS is dominant for the UE. Therefore, the BS is configured to generate the sub-beam of the first beam (e.g., Birst) based on the selected coded beam (e.g., B^). As a result, the coverage area of the sub-beam is within the first beam. In accordance with another embodiment, the BS is configured for generating one of the second beams towards one of the DCSs, and the said DCS is configured for generating the narrow beam that corresponds to the preferred third beam, if the performance metric of the preferred first beam does not exceed that of the preferred third beam by a pre-defined threshold, or the feedback information include no information about the set of preferred first beams. In an example, the status flag (e.g., IsUseNonDCS =0) indicates that the first beam without the DCS is weaker than the selected third beam (e.g., BS -> DCSj* -> UEk). Therefore, the BS is configured to generate one of the second beams towards one of the DCSs, and the said DCS is configured to generate the narrow beam that corresponds to the preferred third beam. In other words, the DCS is configured to select the preferred third beam (i.e., coded beam) as the sub-beam. In an example, a sub-beam is generated within the first beam B^lirst, such as by combining information about a selected first beam B^lirstand an optimal third beam B^ from the set of third beams ..., B^f ], where J is the number of third beams through the DCS.

[0070] The method 100 is beneficial to provide an improved beam selection process with less overhead. Moreover, any region targeted by the one or more first beams can be further provided with the one or more third beams, which is beneficial to improve the amount of information that can be measured with the training signal of the BS. In addition, the feedback information received by the BS provides both the first beam and the third beams that can be used for serving each of the UEs. The method 100 is used to obtain the feedback information, by the BS for the one or more first beams and the one or more third beams in a lesser time. Furthermore, the BS can obtain a more accurate location and beam information, which can be applied to subsequent algorithm design, such as for estimation of the improved angle of arrival (AoA) and angle of departure (AoD) of a line of sight (LoS) condition between the BS and each of the UEs, with reduced cost. Moreover, as the one or more third signals are the encoded signals, thus each third signal can be easily separated from the one or more first signals.

[0071] FIG. 2 is a diagram that depicts a digitally controllable scatterer (DCS) assisted communication system, in accordance with an embodiment of the present disclosure. With reference to FIG. 2, there is shown a diagram of a DCS assisted communication system 200. There is further shown a base station (BS) 202, one or more digitally controllable scatterers (DCSs), such as a first DCS 204A, and a second DCS 204B. There is further shown a first user equipment (UE) 206A and a second UE 206B.

[0072] The DCS assisted communication system 200 is a communication system used for cell search and beam management with the DCS with improved beam selection and reduced overhead. The DCS assisted communication system 200 includes the BS 202 and one or more DCSs, such as the first DCS 204A and the second DCS 204B.

[0073] In operation, the BS 202 is configured to transmit one or more first signals via one or more first beams within a set of first beams, such as each first beam includes a different index, a different direction, and a different coverage area depending on an index of the first beam. For example, the BS 202 is configured to generate the one or more first signals and then transmit the one or more first signals, such as a first signal 208 A and another first signal 208B (as represented by solid lines) via the one or more first beams and within the set of first beams, as further shown and described in FIG. 3. In an implementation, the BS is configured to transmit the one or more first signals via one or more first beams to one or more user equipment (UEs). In addition, the BS 202 is configured to generate one or more second signals and transmit the one or more second signals via one or more second beams towards one or more DCSs, such as each second beam is directed towards a different DCS, and each second signal is a function of the one or more first signals. For example, the BS 202 is configured to generate and transmit a second signal 210 via a second beam towards the first DCS 204A. As a result, two different types of signals, such as the one or more first signals and the one or more second signals, are transmitted by the BS 202. Furthermore, the one or more first beams and the one or more second beams are simultaneously transmitting the corresponding signals while focusing on two disjoint regions.

[0074] In accordance with an embodiment, the BS 202 is configured to select one of the DCSs to generate one of the second beams towards said DCS, for example based on pre-defined locations of the DCSs and the indexes or the coverage areas of the corresponding one or more first beams. For example, the BS 202 is configured to select the first DCS 204A and generate a second beam towards the first DCS 204A based on pre-defined locations of the first DCS 204A. The BS 202 is also configured to generate the second beam based on the indexes or the coverage areas of the corresponding one or more first beams. Thereafter, the BS 202 is configured to transmit the second signal 210 via a second beam towards the first DCS 204A. Similarly, the BS 202 can select the second DCS 204B to generate one of the second beams toward the second DCS 204B based on pre-defined location or coverage area of the second DCS 204B.

[0075] In accordance with an embodiment, each of the DCSs is configured to receive from the BS 202 a set of the unique codes for encoding the second signals into the third signals and / or computing a set of the unique codes for encoding the second signals into the third signals based on the indexes or the coverage areas of the one or more first beams that transmit the one or more first signals, which are comprised as a part of the function in the impinging second signals. In other words, the one or more DCSs are configured to receive or compute the set of the unique codes for encoding the second signals into the third signals based on the indexes or the coverage areas of the one or more first beams. In such embodiments, the unique codes for encoding the second signals into the third signals include frequency modulation codes or phase modulation codes. For example, the third beams undergo a modulation through the first DCS 204A, such that each third (i.e., coded) beam from the one or more third beams is unique and can be easily separated at the reception at a UE. Alternatively, both the BS 202 and the DCSs obtain the codes from a controller.

[0076] There is further provided that each of the DCSs is configured to generate third signals by scattering one or more of the second signals impinging on the DCS, such as each third signal is a coded version of the impinging second signals encoded by the DCS with a unique code from the set of the unique codes. For example, the first DCS 204A is configured to use the unique codes to encode the second signal 210 that is impinging on the first DCS 204A to generate the one or more third signals, such as a third signal 212, for a given second signal, wherein each third signal is generated using one specific code of the unique codes. As a result, each third signal generated by each of the DCSs is the coded version of the impinging second signal. Moreover, each third signal is transmitted via a third beam with a coverage area overlapping with a coverage area of the one or more first beams that transmit the one or more first signals comprised as a part of the function in the impinging second signals. For example, the first DCS 204A is configured to transmit the third signal 212 via a third beam with the coverage area overlapping with the coverage area of the first beam that transmits the first signal 208B comprised as the part of the function in the impinging second signals. In an implementation, each of the DCSs is configured to transmit the third signals via the third beams towards an area of a UE, such as the first UE 206A of the one or more UEs, can be likely located. Moreover, as the one or more third signals are the encoded signals, thus each third signal can be easily separated from the one or more first signals by the one or more UEs. In other words, the set of the unique codes is beneficial for separability within the one or more third signals and the one or more first signals. In accordance with an embodiment, the BS 202 is further configured to provide each of the DCSs with an information about the indexes or the coverage areas of the one or more first beams. For example, the BS 202 is configured to inform the first DCS 204A about the indexes or the coverage areas of the first beam of the one or more first beams. Moreover, the first DCS 204A is configured to generate the third signal 212 by scattering the one or more of the second signals impinging on the first DCS 204A. As a result, the coverage of the third beams generated by each of the DCSs overlaps with the coverage of the one or more first beams within the set of first beams.

[0077] In accordance with an embodiment, each of the DCSs includes subsets of controllable scattering elements. Moreover, in this embodiment, each of the DCSs is configured to control phases of the scattering elements in each of the subsets to generate the third signals transmitted via the third beams. For example, the first DCS 204A includes subsets of controllable scattering elements, and the first DCS 204A is further configured to control phases of the scattering elements in each of the subsets to generate the third signal 212 transmitted via the third beam. Therefore, by controlling the phases of the controllable scattering elements in each subset, a number of beams can be generated by each of the DCSs, and each beam focuses on a different direction. In such embodiment, each of the DCSs is configured to apply scattering patterns to its controllable scattering elements, such as the scattering patterns are based on the indexes or the coverage areas of the one or more first beams that transmit the one or more first signals comprised as a part of the function in the impinging second signals. The third signals are generated to cover either the same region as the one or more first signals generated by the BS 202 or a subregion of the one or more first signals.

[0078] In accordance with an embodiment, each of the UEs is configured for, in response to receiving one or more first signals via one or more first beams and one or more third signals via one or more third beams, obtaining performance metrics for the one or more first beams and the one or more third beams based on the received signals. For example, the first UE 206A is configured to receive the first signal 208A via a first beam and receive the third signal 212 via a third beam. An exemplary implementation of the first beam and the third beam is further shown and described in FIGs. 4A and 4B. Moreover, each of the UEs is configured to select a set of preferred first beams and / or a set of preferred third beams, based on the performance metrics and reports to the BS 202 the feedback information that includes an information about the preferred first beam and / or the preferred third beam. In such embodiment, each of the UEs is configured to measure a signal strength and / or a signal to noise ratio for each of the received signals to obtain performance metrics. Moreover, the computed performance metrics can be used by each of the UEs to determine the quality of the received signals and compare them based on their quality, which can be used to provide the feedback information to the BS 202, such as to improve the efficiency of the BS 202.

[0079] In such embodiments, each of the UEs is configured to select its preferred first beam among the set of preferred first beams and its preferred third beam among the set of preferred third beams based on the performance metrics of the preferred first beams and the preferred third beams. In an example, a preferred first beam index maxi is determined, such as with maxi = i* , where i* is the preferred first beam index i among metric In another example, a preferred third beam index maxj with a status flag is determined, such as with maxj = j*, where j* is the preferred third beam index j among metricDlCS.k1 . Thereafter, t j’ )j each of the UEs is configured to set a status flag to indicate if the performance metric of the UE preferred first beam exceeds that of the UE preferred third beam by a pre-defined threshold value. For example, the first UE 206A is configured to set a status flag to indicate if the performance metric of the first UE 206A preferred first beam exceeds that of the first UE 206A preferred third beam by a pre-defined threshold value. Furthermore, each of the UEs is configured to add the status flag to the feedback information. The status flag is defined to indicate whether the preferred first beam or the preferred third beam is the dominant one. In an implementation, each of the UEs is further configured to add the performance metrics of the preferred first beams and the preferred third beams into the feedback information. Moreover, the feedback information is received by the BS 202 to select the preferred first beams and the preferred third beams based on the performance metrics. Therefore, the feedback information provides information related to both the first beam and the third beams that are used for serving each of the UEs.

[0080] In accordance with an embodiment, each of the UEs is configured to obtain an information on the unique codes for decoding the third signals via a downlink control information from the BS and / or using a pre-defined protocol. Furthermore, each of the UEs is configured to decode the one or more third signals using the downlink control information with reduced cost and reduced noise, and each of the UEs can obtain each channel estimation with or without the DCS. In accordance with an embodiment, each of the UEs is configured to decode the third signals and the corresponding one or more first signals received by the UE using the information on the unique codes. For example, the first UE 206A is configured to receive the unique codes. Thereafter, the unique codes are used by the first UE 206A to decode the third signal 212 and to decode the corresponding first signal (e.g., the first signal 208A). By virtue of decoding the third signals and the corresponding one or more first signals, the first UE 206A can obtain the channel estimation of each beam with the first DCS 204A and without the first DCS 204A. Moreover, the first UE 206A is configured to perform the beam selection by using beam information of the first beam and the third beam and provides the feedback information to inform the BS 202 for the beam selection.

[0081] In accordance with an embodiment, the BS 202 is further configured to receive the feedback information from the one or more UEs, about one or more of the first beams and / or one or more of the third beams. In an example, the BS 202 is configured to use the feedback information to determine the corresponding beam weight by lookup a mapping table. For example, the feedback information provides information of the first beam and / or the third beam that is used for serving the first UE 206A from the one or more UEs. Moreover, the feedback information is computed by the first UE 206A based on the first signal 208A and / or the third signal 212. In an implementation, the BS 202 is configured to select a preferred first beam and / or a preferred third beam from the set of preferred first beams and / or the set of preferred third beams for each of the UEs based on the feedback information reported by said UE. For example, the BS 202 is configured to select the preferred first beam and / or the preferred third beam for the first UE 206A based on the feedback information reported by the first UE 206A.

[0082] The BS 202 is further configured to generate one or more narrow beams for communicating with the one or more UEs. Moreover, each narrow beam includes either a sub-beam of one of the first beams generated by the BS 202 or a beam generated by one of the DCSs that corresponds to one of the third beams and each narrow beam is focused on at least one of the UEs based on the feedback information. In other words, the BS 202 is configured to generate the one or more narrow beams for communicating with the one or more UEs, such as the first UE 206A and the second UE 206B. Moreover, each narrow beam is focused towards at least one of the UEs based on the feedback information. In such embodiment, the BS 202 is configured to focus each of the narrow beams towards at least one of the UEs based on the selection of the preferred first beam and / or the preferred third beam for said UE. In an example, the preferred first beam and / or the preferred third beam are selected from the set of preferred beams for the said UE. Moreover, each of the UEs reports different beam information to the BS 202 in a different transmission process.

[0083] In accordance with an embodiment, the BS 202 is configured to generate a sub-beam of the preferred first beam, the sub-beam having a coverage area that corresponds to the coverage area of the preferred third beam or generating one of the second beams towards one of the DCSs, wherein the said DCS is configured for generating a narrow beam that corresponds to the preferred third beam in response to said second beam. Furthermore, after receiving the beam information, the BS 202 is configured to select the preferred (i.e., a finest or a best) first beam and the preferred third beam (i.e., coded beam) from the reported set of first beams and set of third beams for each of the UEs. In summary, with the assistance of the one or more DCSs, the BS 202 can generate the wide beam and narrow beam at the same time and provide more information for the beam selection. This enumeration generates the narrow beam of the BS 202 based on feedback information about the preferred first beam and the preferred third beam.

[0084] In accordance with an embodiment, the BS 202 is configured to generate the sub-beam of the preferred first beam if the performance metric of the preferred first beam exceeds that of the preferred third beam by a pre-defined threshold. For example, the first UE 206A reports the preferred first beam index, the preferred third beam index, and the status flag to the BS 202. Thereafter, the BS 202 is configured to determine if the performance metric of the preferred first beam exceeds that of the preferred third beam by the pre-defined threshold, then generate the sub-domain of the preferred first beam. In an example, the status flag indicates that the first beam without DCS is dominant for the first UE 206A, and the BS 202 can generate the subbeam of the first beam based on the selected coded beam. As a result, the coverage of the subbeam is within the first beam.

[0085] In accordance with another embodiment, the BS 202 is configured to generate one of the second beams towards one of the DCSs, and the said DCS is configured to generate the narrow beam that corresponds to the preferred third beam if the performance metric of the preferred first beam does not exceed that of the preferred third beam by a pre-defined threshold, or the feedback information comprises no information about the set of preferred first beams. In an example, if the status flag indicates that the first beam without the DCS is weaker than the selected coded beam, then the BS 202 is configured to generate one of the second beams towards one of the DCSs, and the said DCS generating the narrow beam that corresponds to the preferred third beam. In other words, the BS 202 is configured to select the preferred third beam (i.e., coded beam) as the sub-beam.

[0086] The DCS assisted communication system 200 provides an improved beam selection process with less overhead. The DCS assisted communication system 200 further provides the possibility of simultaneously obtaining the information of the one or more first beams and the one or more third beams. Therefore, any region targeted by the first beam can be further provided with the third beam, which is beneficial to improve the amount of information that can be measured with the training signal of the BS 202. In addition, the feedback information received by the BS 202 provides both the first beam and the third beams that are used for serving each of the UEs. Furthermore, the BS 202 can obtain a more accurate location and beam information, which can be applied to subsequent algorithm design, such as for estimation of the improved angle of arrival (AoA) and angle of departure (AoD) of the LoS condition between the BS 202 and each of the UEs.

[0087] FIG. 3 is a flowchart that depicts a beam selection process in a digitally controllable scatterer (DCS) assisted communication system, in accordance with another embodiment of the present disclosure. FIG. 3 is described in conjunction with elements from FIGs. 1 and 2. With reference to FIG. 3, there is shown a flow chart 300 that includes operations 302-to-310.

[0088] At operation 302, the BS 202 (of FIG. 2) and one or more DCSs, such as the first DCS 204A and the second DCS 204B (of FIG. 2), are configured to perform simultaneously for beam selection. The operation 302 further includes operations 302A-to-302C.

[0089] At operation 302A, the BS 202 includes a predefined set of first beams B. Moreover, the BS 202 is configured to perform a beam sweeping process, such as to select a beam or beams in beam sweep set B. In other words, the BS 202 is configured to generate two different types of beams, such as one or more first beams without the DCS (e.g., first DCS 204A) for beam sweeping, and one or more second beams that are always targeting the one or more DCSs (e.g., targeting the first DCS 204A) as previously shown in FIG. 2. In addition, there is a correspondence or a relation between signals of the first beam and the second beam. Furthermore, at operation 302B, the one or more second beams are obtained by the BS 202, such as the one or more second beams focusing on the DCS or on the one or more DCSs. Thereafter, the BS 202 is configured to obtain signals sent on corresponding beams, since the BS 202 is configured for handling of the one or more second beams, the second signal design, and transmission. In addition, at operation 302C, each of the one or more DCSs (e.g., the first DCS 204A) is configured to apply DCS scattering pattern according to the first beam / beams id / ids.

[0090] In an example, the controllable scattering elements in the one or more DCSs are divided into J subsets by creating J subpanels. Moreover, by controlling the phases of the scattering elements in each subset, J number of third beams can be generated by the one or more DCSs, and each third beam focuses on a different direction. In an example, F isused to denote a scattering pattern matrix of a beam j of the one or more DCSs, which is related to the first beam, such as a first beam i.The scattering pattern is a function of scattering phases <DlcSj applied by the controllable scattering elements of the one or more DCSs. Moreover, the one or more DCSs will be informed by the BS 202 about the index or coverage of the first beam. Then based on the first beam index, the scattering pattern F(4>pCS) of a beam j -th DCS subset can be configured online or offline. Moreover, the third beam of the one or more DCSs covers a subregion or the same region as that of the first beam.

[0091] At operation 304, each DCS from the one or more DCSs is configured to generate the one or more third signals by scattering one or more of the second signals impinging on the corresponding DCS. Moreover, each third signal is a coded version of the impinging second signals encoded by the corresponding DCS with a unique code and transmitted via a third beam with a coverage area overlapping with a coverage area of the one or more first beams that transmit the one or more first signals comprised as a part of the function in the impinging second signals. In an example, each DCS from the one or more DCSs is configured to select J+l number of codewords CDCS. , and assign for each beam j = 1, ..., J generated by the corresponding DCS, one of the codewords. Moreover, the value of the J and the codewords CDCS. are pre-defined for both the one or more DCSs and the one or more UEs. In an implementation, the codewords CDCS. can be for example frequency modulation codes or phase modulation codes. Furthermore, each UE can obtain each channel estimation with or without the DCS H® , H®Si;k, ..., H®S; fc, such as by applying received signal processing based on the chosen modulation and codes for separability. In an example, the is used to denote the channel estimation without the DCS (e.g., without the first DCS 204A) measured at a UE k (e.g., the first UE 206A) when the first beam i is used at the BS 202. Similarly, the H[)CS7-,fc is used to denote the channel estimation for the DCS channel via beam j measured at the UE k when the first beam i is used at the BS 202. Thereafter, at operation, 306, it is assessed if all the beams have undergone tested or not. Moreover, if all the beams are not tested, then the operations 302 and 304 are repeated, otherwise operation 308 is executed, which further includes two different operations, such as an operation 308A and an operation 308B.

[0092] At operation, 308A, each of the UEs is configured to obtain performance metrics for the one or more first beams and the one or more third beams based on the received signals. Thereafter, each of the UEs is configured to select a set of preferred first beams and / or a set of preferred third beams, based on the performance metrics. In an implementation, the performance metrics can be selected as metricQkor metricDlCS.k,. In an example, a metric^k= RSRPQk / SNR0lkand metricDlCS.k= RSRP^cs.k / SNRD1CS.Kare selected, where RSRP and SNR are signal strength and signal to noise ratio metrics. Furthermore, the RSRPQk / SNR0lkis the RSRP / SNR of / -th first beam without the DCS, RSRP^cs.k / SNRDlCS.kis the RSRP / SNR of j-th coded beam with the DCS scattering related to the i-th first beam. In an example, each of the UEs is configured to determine a maximal (i.e., preferred) first beam index maxi, such as maxi = i* , where i* is the maximal (i.e., preferred) first beam index i among metric +

[0093] ^Jj=1metricDiCS k] . In another example, each of the UEs is configured to determine a maximal

[0094] 7 7 Jl

[0095] (i.e., preferred) coded beam index maxj with the status flag and maxj = j*, where j* is the maximal (i.e., preferred) third beam index j among \ metricDlCS.k1 . Thereafter, the status flag t j' is used to indicate whether the selected first beam or the selected third beam is the dominant one.

[0096] Each of the UEs is further configured to report a feedback information to the BS 202, such as the feedback information includes an information about the set of preferred first beams and / or the set of preferred third (or coded) beams. Moreover, each of the UEs reports different beam information to the BS 202 in a different transmission process. In an example, for cell search process, the preferred first beam index maxi, the preferred third beam index maxj, and the status flag IsUseNonDCS are fed back to the BS 202 by each of the UEs. Further, if more feedback information is allowed by the feedback mechanism, then each of the UEs can additionally report the set of preferred (or best) first beams index, the set of preferred (or best) third beams index, the metric^k, metricDlCS.kand the status flag IsUseNonDCS to the BS 202. Thereafter, at operation 308B, after receiving the beam information, the BS 202 selects a preferred first beam and a preferred third beam from the reported set of first beams and the set of third beams for each of the UEs.

[0097] At operation, 310, the BS 202 is configured to generate one or more narrow beams for communicating with the one or more UEs, such as each narrow beam includes either a subbeam of one of the first beams generated by the BS or a beam generated by one of the DCSs that corresponds to one of the third beams and each narrow beam is focused towards one of the UEs based on the feedback information. In an example, if IsUseNonDCS =1, which indicates the first beam without the DCS is dominant for the UE, then the BS 202 can generate a subbeam of the first beam Birstbased on the selected coded beam such as the coverage of the sub-beam is within the first beam and is designed based on the coverage of the selected coded beam. In another example, if IsUseNonDCS =0, which indicates the first beam without the DCS is weaker than the selected third beam (e.g., BS -> DCSj* -> UEk), then the BS 202 is configured to determine the selected third beam as a sub-beam.

[0098] FIG. 4A and 4B are different diagrams that depict a beam generation process in a digitally controllable scatterer (DCS) assisted communication system, in accordance with different embodiments of the present disclosure. FIGs. 4A and 4B are described in conjunction with elements from FIGs. 1 and 2. With reference to FIGs. 4A and 4B there is shown a diagram 400A and a diagram 400B respectively that includes the BS 202, the first DCS 204A, and the first UE 206A.

[0099] With reference to FIG. 4A, there is shown BS 202 that includes a predefined set of first beams B. In an example, a first beam 402, such as a first beam B^lirstis selected through the sweeping process among the set of first beams B, as shown by an arrow, which is directed from a right side (i.e., from beam sweep set) to a left side. Moreover, the first beam 402 is generated by the BS 202. In an example, a first beam set is a set of first beams that are selected through the beam sweeping process among the beam set B. In addition, a second beam 404, such as a second beam Be^,ndis constructed by the BS 202. The second beam 404 is designed to focus on the DCS 204A. Furthermore, a second beam set Bs'ecOndis an example of a set of second beams constructed by the BS 202, which focuses on the set of DCS {DCS}. In addition, the signal transmitted on the first beam 402 and the second beam 404 is the same when only one first beam 402 is selected. The signal transmitted on the second beam 404 is a function of the signals transmitted on the first beam 402. In an example, third beams {B^J }j are the third (or coded) beams that are generated by the first DCS 204 A due to the scattering of the second beam 404. For example, a third beam 406 is generated by the first DCS 204A due to the scattering of the second beam 404, similarly, other third beams are generated, as shown in FIG. 4A.

[0100] In an implementation, the BS 202 is configured to receive a feedback information from the first UE 206A, about the first beam 402 and / or one or more third beams, such as the third beam 406, and the feedback information is computed by the first UE 206A based on the first signal 208A (of FIG. 2) and / or the one or more third signals, such as the third signal 212 (of FIG. 2) received by the first UE 206A. Thereafter, the BS 202 is configured to generate one or more narrow beams for communicating with the first UE 206A. Moreover, each narrow beam includes either a sub-beam, such as a sub-beam 408 (as shown in FIG. 4B) of one of the first beam 402 generated by the BS 202 or a beam generated by the first DCS 204 A that corresponds to the third beams, such as the third beam 406. In addition, the narrow beam is focused on the first UE 206A based on the feedback information. Moreover, the sub-beam 408, such as a first subbeam isgenerated within the first beam 402, such as within the first beam Birst. In an example, the sub-beam 408 is generated by combining information about the selected first beam Birstand an optimal coded beam B^Cp from the set of coded beams where J is the number of coded beams through the DCS.

[0101] FIG. 5 is a diagram that depicts a digitally controllable scatterer (DCS) applying scattering patterns to controllable scattering elements, in accordance with an embodiment of the present disclosure. FIG. 5 is described in conjunction with elements from FIGs. 1, 2, 3, 4A, and 4B. With reference to FIG. 5, there is shown a diagram 500.

[0102] In an example, each third signal is a coded version of the impinging second signals encoded by the corresponding sub-DCS with a unique code, such as with phase coding. In an example, a sub-DCS j applies the coded scattering pattern sequence during the u-th time sample, which corresponds to the coding time interval T. In an implementation, the unique codes for encoding the second signals into the third signals include frequency modulation codes or phase modulation codes. For example, a unique code with a different codeword [c C is applied per subset j of DCS elements. Further, the unique code is applied per the third beam of the DCS, such as by using a codeword CDCS. = [c C that is applied to the DCS beam j that is generated by the subset of elements j. Thereafter, the third beam allows a UE k (e.g., the first UE 206A) to estimate the N + 1 signals the non- DCS channel of z-th first beam observed at UE k, HQCS^.kis the DCS generated channel observed at the UE k corresponding to the j-the third beam of the i-th first beam. In addition, x[u] is the first signal transmitted by the BS 202 at the / / -th time sample on the z-th first beam. Therefore, each of the UEs can obtain each channel estimation with or without the DCS Hofc, determining the x[u] as reference signals or specific sequences. FIGs. 6A and 6B are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam selection with DCS in line of sight (LOS) condition, in accordance with different embodiments of the present disclosure. FIGs. 6A and 6B are described in conjunction with elements from FIGs. 1, 2, 4A, and 4B. With reference to FIG. 6A there is shown a diagram 600A that depicts a DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2). With reference to FIG. 6B there is shown a diagram 600B that depicts a DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2).

[0103] With reference to FIGs. 6A and 6B, there is shown that the first DCS 204A is deployed between the BS 202 and the first UE 206A. Moreover, a line of sight (LOS) condition exists between the BS 202 and the first UE 206A, such as with a first beam 602, as shown in FIG. 6 A. Further, another LOS condition exists between the BS 202 and the first DCS 204A, such as with a second beam 604. In addition, yet another LOS condition exists between the first DCS 204A and the first UE 206A, such as with a third beam 606. Moreover, in the LOS condition, a beam search mode exists, and the third beam 606 is generated by the first DCS 204A based on the scattering pattern and phase coding codewords, which cover the same region as the first beam 602. In addition, the beam selection results in the BS 202 selecting a sub-beam based on the reported best first beam and the preferred third beam, as shown in FIG. 6B.

[0104] In an implementation, the BS 202 generates the first beam 602 and the second beam 604 at the same time. The first beam 602 is used for the beam sweeping and the second beam 604 always focuses on the first DCS 204A during the search process. Both the first beam 602 and the second beam 604 send the same signal simultaneously. In an example, the scattering elements in the first DCS 204A are divided into J subsets by creating J subpanels. The first DCS 204A is informed by the BS 202 about a first beam index or the coverage of the first beam 602. Then, the third beams are generated, such as the third beam 606 is generated by applying the DCS scattering pattern corresponding to the first beam index. The coverage of the one or more third beams generated by the first DCS 204A overlaps with the coverage of the first beam 602. In an example, scattering pattern F °f J "th subpanel of the first DCS 204A is computed offline. Further, the subpanel of the first DCS 204A can obtain the scattering pattern F based on the first beam index or its corresponding coverage area. In an example, the scattering pattern F ( pCs;°f J’th subpanel of the first DCS 204A is computed online. The scattering pattern F iscalculated online or offline based on the location of the BS 202 and the coverage area of the first beam. Furthermore, the scattering pattern isupdated synchronously with the first beam sweeping, where the superscript i is the first beam index. Each subpanel of the first DCS 204A applies the codewords CDCS. to the impinging signal. Thereafter, the first UE 206A is configured to receive the signals and the first UE 206A decodes the reference signals with the codewords CDCS. and obtains the RSRPQk, RSRPDlCSi k,..., RSRPCS. RSRPCS] kof each z-th first beam and j-th DCS scattered beam (RSRP is an example of the performance metric). Then, by comparing the RSRP of each beam, the first UE 206A obtains the index of the strongest first beam maxi = i* and third beam index maxj = j* of the first DCS 204A. Furthermore, the first UE 206A is configured to define a parameter IsUseNonDCS as a status flag, and Athreis defined as a threshold. Because of the existence of the LOS link between the BS 202 and the first UE 206A, if RSRPQk— RSRP^cs .t k> the channel without the DCS Ho / kis dominant, and set the status flag IsUseNonDCS = 1. The strongest coded beam reflected by the DCS is used by the first UE 206A to identify an accurate beam information of the first UE 206A. The first UE 206A further reports the best first beam index maxi = i*, the bestthird beam index maxj = j*, and the status flag Is UseNonDCS to the BS 202. The BS 202 can obtain the improved beam information and apply it to subsequent processes or algorithm designs to select or construct a sub-beam within the selected first beam directly to the first UE 206A, as shown in FIG. 6B. In an implementation, beam selection is performed by the DCS, such as by the first DCS 204A in the LOS condition and reports all beam information. In another implementation, beam selection or beam construction is performed by the BS 202. Moreover, the first UE 206 A reports cardinality of the set of preferred first beams index, the set of preferred third beams index, the status flag IsUseNonDCS, and all beam performance metric RSRPQk, RSRPCS.k(1 = 0,1, ... |B| — l, j = 0,1, ... , J — 1) to the BS 202 and / or the DCS and / or the controller entity performing beam selection or beam construction.

[0105] FIGs. 7A and 7B are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam selection with DCS in Non-line of sight (NLOS) condition, in accordance with different embodiments of the present disclosure. FIGs. 7A and 7B are described in conjunction with elements from FIGs. 1, 2, 4A, and 4B. With reference to FIG. 7A there is shown a diagram 700A that depicts a DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2). With reference to FIG. 7B there is shown a diagram 700B that depicts the DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2).

[0106] With reference to FIG. 7 A, there is shown that the first DCS 204A is deployed between the BS 202 and the first UE 206A. Moreover, non-line of sight (NLOS) condition exists between the BS 202 and the first UE 206A. For example, due to the presence of an obstacle 702, there exists the NLOS condition on a first beam 704. Further, a line of sight (LOS) condition exists between the BS 202 and the first DCS 204A, such as on a second beam 706. In addition, another line of sight (LOS) condition exists between the first DCS 204A and the first UE 206A, such as with a third beam 708. Moreover, in a beam search mode of NLOS condition, the third beam, such as the third beam 708 is generated by the first DCS 204A based on the scattering pattern and phase coding codewords, which cover the same region as the first beam 704.

[0107] In an implementation, the first UE 206A is configured to define a parameter IsUseNonDCS as a status flag and set Athreas a threshold. Moreover, in the NLOS condition, there is no LOS link between the BS 202 and the first UE 206A. Based on the deployment of the first DCS 204A, the LOS link exists between the BS 202 and the first DCS 204A and also between the first DCS 204A and the first UE 206A. Moreover, if RSRPQk— RSRP^cs .t k<thre, the status flag IsUseNonDCS = 0, then the channel from the BS 202 to the first DCS 204A and then to the first UE 206A (i.e., BS -> DCS UE) can be used not only for the generation of the third beam 708 but also the transmission channel for data. As the BS 202 receives the beam information reported by first UE 206A, then the BS 202 (e.g., the antennas of the BS 202) will no longer separate into two subpanels (or ports), as shown in FIG. 7B. Moreover, the BS 202 only generates the second beam 706 focus to the first DCS 204A, then selects the third beam 708 as the sub-beam for data transmission, as shown in FIG. 7B. In other words, in the NLOS condition, the BS 202 selects a sub-beam based on the reported preferred first beam 704 and reported the third beam 708.

[0108] FIGs. 8 A, 8B, and 8C are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam mapping after receiving beam information in the line of sight (LOS) condition, in accordance with different embodiments of the present disclosure. FIGs. 8 A, 8B, and 8C are described in conjunction with elements from FIGs. 1, 2, 4A, and 4B. With reference to FIG. 8A there is shown a diagram 800A that depicts a DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2). With reference to FIG. 8B there is shown a diagram 800B that depicts the DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2). With reference to FIG. 8C there is shown a diagram 800C that depicts the DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2).

[0109] With reference to FIG. 8 A, there is shown that the first DCS 204A is deployed between the BS 202 and the first UE 206A. Moreover, a line of sight (LOS) condition exists between the BS 202 and the first UE 206A. Further, another line of sight (LOS) link exists between the BS 202 and the first DCS 204A. In addition, yet another line of sight (LOS) link exists between the first DCS 204A and the first UE 206A. Moreover, the first UE 206A reports a preferred (or best) beam information, such as through a preferred first beam 802 that includes the preferred first beam index, selected best third beam index with the first DCS 204A, and a status flag (e.g., IsUseNonDCS 1) to the BS 202. Moreover, there exists beam mapping after receiving the beam information in the LOS condition.

[0110] With reference to FIG. 8A, there is shown that the first UE 206A selects the preferred first beam 802 and a preferred third beam 804, then reports the preferred first beam 802 and the preferred third beam 804 to the BS 202. Moreover, with reference to FIG. 8B, there is shown a coverage area of sub-beams corresponding to a third beam index, such as shown by a sub-beam 806. There is further shown a coverage area 808 of the first beam 802 (of FIG. 8A). Furthermore, based on the reported preferred coded beam index, the BS 202 selects a sub-beam 810 directly towards the first UE 206A, as shown in FIG. 8C. Moreover, as the geometrical information of the coverage area, is known, and the BS 202 and first DCS 204A are fixed, then the scattering pattern F(4>pCS) of the first DCS 204A ]-th subset in i-th first beam can be calculated offline. The BS 202 recognizes the coverage of each coded beam generated by the first DCS 204A. In an example, a narrow sub-beam weight w- can be calculated offline by the BS 202 according to the DCS coded beam coverage. Further, a mapping order table between the narrow sub-beam weight Wj and each selected coded beam index j is stored on the BS 202. After receiving the 7 * best beam information, the BS 202 determines the corresponding beam weight by lookup the mapping table.

[0111] FIGs. 9A and 9B are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam mapping after receiving beam information in No-line of sight (NLOS) condition, in accordance with different embodiments of the present disclosure. FIGs. 9A and 9B are described in conjunction with elements from FIGs. 1, 2, 4A, and 4B. With reference to FIG. 9A there is shown a diagram 900A that depicts a DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2). With reference to FIG. 9B there is shown a diagram 900B that depicts the DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2).

[0112] With reference to FIG. 9 A, there is shown that the first DCS 204A is deployed between the BS 202 and the first UE 206A. Moreover, due to the presence of the obstacle 702, there exists noline of sight (NLOS) condition between the BS 202 and the first UE 206A. Further, there exists beam mapping after receiving beam information in the NLOS condition. Further, a line of sight (LOS) condition exists between the BS 202 and the first DCS 204A. In addition, another line of sight (LOS) condition exists between the first DCS 204A and the first UE 206A. In addition, the first UE 206 A reports the preferred beam information to the BS 202, such as reports including a best first beam index, a selected preferred coded beam index with the first DCS 204A, and a status flag IsUseNonDCS=0. In other words, the first UE 206A selects a preferred first beam 902 and a preferred third beam 904, and then reports to the BS 202, as shown in FIG. 9 A. In addition, based on the reported preferred third beam index, the BS 202 generates the second beam 906, which focuses on the first DCS 204A and selects the reported selected third beam with the first DCS 204A as the sub-beam, as shown in FIG. 9B. Optionally, the selection is made by the BS 202 or any other device. In an example, as the BS 202 receives the beam information reported by the first UE 206A, by detecting the status flag IsUseNonDCS = 0, the first beam is eliminated and generates a single second beam focus on the first DCS 204A instead. Moreover, the BS 202 informs the first DCS 204A about the selected coded beam index, then the first DCS 204A adjusts the phases of elements to generate the selected third beam as the sub-beam for data transmission, as shown in FIG. 9B. FIGs. 10A, 1OB, IOC, and 1OD are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam selection with a DCS in multipleuser scenarios, in accordance with different embodiments of the present disclosure. FIGs. 10A, 10B, IOC, and 10D are described in conjunction with elements from FIGs. 1, 2, 4 A, and 4B. With reference to FIG. 10A there is shown a diagram 1000A that depicts a DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2). With reference to FIG. 10B there is shown a diagram 1000B that depicts the DCS assisted communication system. With reference to FIG. IOC there is shown a diagram 1000C that depicts the DCS assisted communication system. With reference to FIG. 10D there is shown a diagram 1000D that depicts the DCS assisted communication system.

[0113] With reference to FIG. 10A, there is shown that the first DCS 204A is deployed between the BS 202 and the first UE 206A for beam selection with the first DCS 204A in multiple-user scenarios, such as in the presence of the second UE 206B that exists in other direction. In an implementation, the BS 202 is configured to serve K number of UEs, such as to serve the first UE 206A and the second UE 206B. Moreover, a line of sight (LOS) condition exists between the BS 202 and a kth UEk, such as the first UE 206A. In addition, another LOS condition exists between the BS 202 and the first DCS 204A. Furthermore, yet another LOS condition exists between the first DCS 204A and the kth UEk, such as the first UE 206A. There is further shown that during the beam search process in multi-user scenarios, the first UE 206A and the second UE 206B are in different first beams and different third beams, as shown in FIG. 10A and 10B. For example, the first UE 206A is receiving a first beam 1002, and a third beam 1004, as shown in FIG. 10A. Similarly, the second UE 206B is receiving a first beam 1006 and a third beam 1008, as shown in FIG. 10B. Furthermore, each UE reports a preferred first beam and a preferred third beam to the BS 202. For example, the first UE 206A reports a preferred first beam 1010, and a preferred third beam 1012 to the BS 202. Similarly, the second UE 206B reports a preferred first beam 1014 and a preferred third beam 1016 to the BS 202, as shown in FIG. 10C. The first UE 206A and the second UE 206B are further configured to transmit a feedback information to the BS 202, which is configured to receive the feedback information from each of the UEs, such as from the first UE 206 A and the second UE 206B. Thereafter, the BS 202 is configured to generate multiple sub-beams for data transmission. For example, a sub beam 1018 is generated for the first UE 206A and a sub-beam 1020 is generated for the second UE 206B, as shown in FIG. 10D. In an implementation, during the beam selection process, the K number of UEs decode the reference signals (received first signals and third signals) with the codewords Cdcs. and obtain the first beam for a UE k. Then, by comparing the RSRP of each beam, the UE k gets the index of the strongest first beam maxikand corresponding DCS coded beam index maxjk. Moreover, each of the K number of UEs reports the preferred first beam index, preferred third beam index, and status flag to the BS 202. Furthermore, in LOS conditions and during beam mapping, the BS 202 generates multiple sub-beams for multi-users based on the reported beam information.

[0114] FIGs. 11 A, 1 IB, 11C, and 1 ID are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam selection with multiple DCSs in multiple-user scenarios, in accordance with different embodiments of the present disclosure. FIGs. 11 A, 1 IB, 11C, and 1 ID are described in conjunction with elements from FIGs. 1, 2, 4A, and 4B. With reference to FIG. 11 A there is shown a diagram 1100A that depicts a DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2) for beam selection with multiple DCS in multiple-user scenarios. With reference to FIG. 11B there is shown a diagram 1100B that depicts the DCS assisted communication system for beam selection with multiple DCS in multiple-user scenarios. With reference to FIG. 11C there is shown a diagram 1100C that depicts the DCS assisted communication system for beam selection with multiple DCS in multiple-user scenarios. With reference to FIG. 1 ID there is shown a diagram HOOD that depicts the DCS assisted communication system for beam selection with multiple DCS in multiple-user scenarios.

[0115] In an implementation, the BS 202 is configured to serve K number of UEs with D number of DCSs deployed between the BS 202 and the K number of UEs. With reference to FIG. 11 A and 1 IB, there is shown a beam search process with multiple DCSs in multi-user scenarios, where the K number of UEs, such as the first UE 206A and the second UE 206B are in the different first beams, and the second beams are focusing on different DCSs. For example, the first DCS 204A is deployed between the BS 202 and the first UE 206A. as shown in FIG. 11 A. Moreover, a line of sight (LOS) condition exists between the BS 202 and a kth UEk, such as the first UE 206 A through a first beam 1102, as shown in FIG. 11 A. In addition, another LOS condition exists between the BS 202 and a DCSd, such as the first DCS 204A through a second beam 1104. In an example, the BS 202 is configured to generate the second beam 1104 with the first DCS 204A by looking up a mapping table. Furthermore, yet another LOS condition exists between the DCSd, such as the first DCS 204A and the kth UEk, such as the first UE 206A through a third beam 1106, as shown in FIG. 11 A. Similarly, the second DCS 204B is deployed between the BS 202 and the second UE 206B, as shown in FIG. 11B. In addition, a LOS condition exists between the BS 202 and the second UE 206B through a first beam 1108, as shown in FIG. 11B. In addition, another LOS condition exists between the BS 202 and the second DCS 204B through a second beam 1110. In an example, the BS 202 is configured to generate the second beam 1110 with the second DCS 204B by looking up a mapping table. Furthermore, yet another LOS condition exists between the second DCS 204B and the second UE 206B through a third beam 1112, as shown in FIG. 1 IB.

[0116] In an implementation, as the geometrical information of the coverage area is known and the locations of the BS 202, the first DCS 204A and the second DCS 204B are fixed. Moreover, the relation between the first beams and the first DCS 204A and the second DCS 204B can be predefined offline based on the distance and obstacle information. The mapping order of first beam index - DCS index can be stored on the BS 202. In addition, in the beam selection process, the BS 202 generates the second beams with the corresponding DCS by looking up the mapping table, shown in FIGs. 11 A and 1 IB. Moreover, K number of UEs decode the reference signals with the codewords Cdcs. nd obtain the RSRPQk, RSRPCSi k,..., RSRPCS.k,..., RSRP^CS] kof i-th first beam for UE k. Then, by comparing the RSRP of each beam, a UE k gets the index of the strongest first beam maxikand its corresponding third beam index maxjk. In an example, each of K number of UEs reports a preferred first beam index, a preferred third beam index, and a status flag to the BS 202. Further, the BS 202 obtains the corresponding DCS index by receiving the preferred first beam index. Moreover, according to the beam mapping method in LOS conditions, the BS 202 generates multiple sub-beams for multi-users based on the reported beam information. For example, with reference to FIG. 11C, there is shown that each UE reports a preferred first beam and a preferred third beam to the BS 202. For example, the first UE 206A reports a preferred first beam 1114, and a preferred third beam 1116 to the BS 202. Similarly, the second UE 206B reports a preferred first beam 1118, and a preferred third beam 1120 to the BS 202. Thereafter, each UE is configured to transmit the feedback information to the BS 202. Furthermore, after receiving the feedback information from multi-users, the BS 202 generates multiple sub-beams for data transmission. For example, a sub-beam 1122 is generated for data transmission towards the first UE 206A and a sub-beam 1124 is generated for data transmission towards the second UE 206B, as shown in FIG. 1 ID.

[0117] FIGs. 12A and 12B are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam selection with multiple first beams, in accordance with different embodiments of the present disclosure. FIGs. 12A and 12B are described in conjunction with elements from FIGs. 1, 2, 4A, and 4B. With reference to FIG. 12A there is shown a diagram 1200A that depicts a DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2) for beam selection with multiple first beams. With reference to FIG. 12B there is shown a diagram 1200B that depicts the DCS assisted communication system for beam selection with multiple first beams.

[0118] With reference to FIG. 12B, there is shown a beam selection process with the first DCS 204A in multi-user scenarios with multiple first beams, such as with P first beams that are generated at the same time by the BS 202, and P > 1. In other words, the BS 202 generates P number of first beams at the same time, where P > 1. Moreover, the K number of UEs, such as the first UE 206A and the second UE 206B are in the different first beams, and the second beam is focusing on the first DCS 204A. In an implementation, the BS 202 is configured to serve K number of UEs with the first DCS 204A deployed between the BS 202 and the K number of UEs, such as the first UE 206A and the second UE 206B. Moreover, a line of sight (LOS) condition exists between the BS 202 and a kth UEk, such as the first UE 206A through a first beam 1202, as shown in FIG. 11 A. In addition, another LOS condition exists between the BS 202 and the second UE 206B through a first beam 1204. In addition, yet another LOS condition exists between the BS 202 and a DCSd, such as the first DCS 204A through a second beam 1206. Furthermore, another LOS condition exists between the DCSd, such as the first DCS 204A and the kth UEk, such as the first UE 206A through a third beam 1208, as shown in FIG. 12 A. There is further shown a LOS condition between the first DCS 204A and the second UE 206B through a third beam 1210.

[0119] In an example, the second beam focuses on the first DCS 204A, which contains multiple first signals and is implemented via aggregation / superposition of the signals in the first beams. Then by applying the scattering pattern and codewords, / coded beams are generated by first DCS 204A, which cover the same regions of the multiple first beams. Furthermore, K number of UEs decode the reference signals with the codewords Cdcs. and obtain the RSRPQ ^ , RSRPCSi k,..., RSRPCS.k,..., RSRPCS] kof i-th first beam and J third beams for a UE k, such as the first UE 206A. Then, by comparing the RSRP of each beam, the UE k gets the index of the strongest first beam maxikand its corresponding DCS coded beam index maxjk. Each of K UEs reports the preferred first beam index, the preferred third beam index, and the status flag to the BS 202. In other words, the first UE 206A and the second UE 206B are configured to report to the BS 202 the feedback information including an information about the set of preferred first beams and / or the set of preferred third beams. Moreover, according to the beam mapping method in LOS conditions, the BS 202 generates multiple sub-beams for multi-users based on the reported beam information. For example, the BS 202 generates a sub-beam 1212 for communicating with the first UE 206A and generates a sub-beam 1214 for communicating with the second UE 206B, as shown in FIG. 12B.

[0120] FIGs. 13 A and 13B are different diagrams that depict different digitally controllable scatterer (DCS) assisted communication systems for beam selection with multiple first beams and multiple DCSs, in accordance with different embodiments of the present disclosure. FIGs. 13 A and 13B are described in conjunction with elements from FIGs. 1, 2, 4A, and 4B. With reference to FIG. 13 A there is shown a diagram 1300A that depicts a DCS assisted communication system (i.e., the DCS assisted communication system 200 of FIG. 2) for beam selection with multiple first beams and multiple DCSs. With reference to FIG. 13B there is shown a diagram 1300B that depicts the DCS assisted communication system for beam selection with multiple first beams and multiple DCSs.

[0121] With reference to FIG. 13 A, there is shown a beam selection process with multiple first beams and multiple DCSs, such as P number of first beams are generated at the same time by the BS 202, P > 1. Moreover, K number of UEs are in the different first beams, and the corresponding second beams are focusing on different DCSs, such as the first DCS 204A and the second DCS 204B. In other words, the BS 202 is configured to serve K number of UEs with multiple DCSs, such as the first DCS 204A and second DCS 204B that are deployed between the BS 202 and the K number of UEs, such as the first UE 206A and the second UE 206B.

[0122] Moreover, a line of sight (LOS) condition exists between BS-UEk, BS-DCSdand DCSd-UEk. For example, between the BS 202 and a kth UEk, such as the first UE 206A through a first beam 1302, as shown in FIG. 11 A. In addition, another LOS condition exists between the BS 202 and the second UE 206B through a first beam 1308. In addition, yet another LOS condition exists between the BS 202 and a DCSd, such as the first DCS 204A through a second beam 1304. Similarly, another LOS condition exists between the BS 202 and the second DCS 204A through a second beam 1310. Furthermore, yet another LOS condition exists between the DCSdand the kth UEk, such as between the first DCS 204A and the first UE 206A through a third beam 1306, as shown in FIG. 13 A. There is further shown a LOS condition between the second DCS 204B and the second UE 206B through a third beam 1312. In an example, multiple first beams are generated at the same time by BS.

[0123] In an implementation, the BS 202 generates P number of first beams at the same time, where P > 1. Moreover, the BS 202 generates P' number of second beams that focus on the different DCSs, each second beam contains only one first signal in the corresponding first beam. In an example, the first set of beams and the second set of beams include different numbers of beams. Thereafter, by applying the scattering patterns and codewords, J number of coded beams are generated by multiple DCSs, which cover the same regions as that of the multiple first beams. In addition, K number of UEs decode the reference signals with the codewords CDCS. and obtain the first beam for UE k. Then, by comparing the RSRP of each beam, a UE k gets the index of the preferred first beam maxikand its corresponding third beam index maxjk. Thereafter, each of the K number of UEs reports the preferred first beam index, the preferred third beam index, and the status flag to the BS 202. In addition, according to the beam mapping in LOS condition, the BS 202 generates multiple sub-beams for multi-users based on the reported beam information. In other words, after receiving the feedback information from each of the UE, the BS 202 generates multiple subbeams for data transmission. For example, the BS 202 generates a sub-beam 1314 for communicating with the first UE 206A, as shown in FIG. 13B. Similarly, the BS 202 generates a sub-beam 1316 for communicating with the second UE 206B, as shown in FIG. 13B.

[0124] FIG. 14A to FIG. 14E are illustrations of different exemplary configurations of scattering surfaces of a digitally controllable scatterer (DCS), in accordance with different embodiments of the present disclosure. FIGs. 14A to 14E are shown in conjunction with elements from FIGs. 2 to 13B. As shown in FIG. 14A to FIG. 14E, a DCS may have different configurations or different shapes. For instance, the DCS may have either a planar or a non-planar structure. For example, with reference to FIG. 14A there is shown a diagram 1400A that depicts an exemplary configuration of scattering surface (i.e., a planar shape) of the DCS. With reference to FIG. 14B, there is shown a diagram 1400B that depicts an exemplary configuration of scattering surface (i.e., non-planar shape) of the DCS. With reference to FIG. 14C, there is shown a diagram 1400C that depicts yet another exemplary configuration of scattering surface (i.e., non- planar shape) of the DCS. With reference to FIG. 14D, there is shown a diagram 1400D that depicts another exemplary configuration of scattering surface (i.e., non-planar shape) of the DCS. With reference to FIG. 14E, there is shown a diagram 1400E that depicts that a distributed configuration is also valid for the implementation of a DCS. Multiple DCSs can also be implemented by logically splitting a DCS into multiple DCSs through subsets of scattering elements.

[0125] Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "have", "is" used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. The word "exemplary" is used herein to mean "serving as an example, instance or illustration". Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or to exclude the incorporation of features from other embodiments. The word "optionally" is used herein to mean "is provided in some embodiments and not provided in other embodiments". It is appreciated that certain features of the present disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable combination or as suitable in any other described embodiment of the disclosure.

Claims

CLAIMS1. A method (100) of beam management in a Digitally Controllable Scatterer, DCS, assisted communication system (200), comprising: a base station, BS, (202) transmitting one or more first signals via one or more first beams within a set of first beams, wherein each first beam has a different index, a different direction and a different coverage area depending on an index of the first beam, the BS (202) transmitting one or more second signals via one or more second beams towards one or more Digitally Controllable Scatterers, DCSs, wherein each second beam is directed towards a different DCS, and each second signal is a function of the one or more first signals, and each of the DCSs, generating third signals by scattering one or more of the second signals impinging on the DCS, wherein each third signal is a coded version of the impinging second signals encoded by the DCS with a unique code and transmitted via a third beam with a coverage area overlapping with a coverage area of the one or more first beams that transmit the one or more first signals comprised as a part of the function in the impinging second signals.

2. The method (100) of claim 1, further comprising: the BS (202) receiving a feedback information from one or more user equipment, UEs, about one or more of the first beams and / or one or more of the thirds beams, wherein the feedback information is computed by each of the one or more UEs based on the one or more first signals and / or the one or more third signals received by the UE, and the BS (202) generating one or more narrow beams for communicating with the one or more UEs, wherein each narrow beam comprises either a sub-beam of one of the first beams generated by the BS or a beam generated by one of the DCSs that corresponds to one of the third beams, and each narrow beam is focused on one of the UEs based on the feedback information.

3. The method (100) of claim 2, further comprising: each of the UEs, in response to receiving one or more first signals via one or more first beams and one or more third signals via one or more third beams: obtaining performance metrics for the one or more first beams and the one or more third beams based on the received signals,selecting a set of preferred first beams and / or a set of preferred third beams, based on the performance metrics, and reporting to the BS (202) the feedback information comprising an information about the set of preferred first beams and / or the set of preferred third beams, and the BS (202) selecting a preferred first beam and / or a preferred third beam from the set of preferred first beams and / or the set of preferred third beams for each of the UEs based on the feedback information reported by said UE.

4. The method (100) of claim 3, wherein each of the narrow beams is focused on one of the UEs based on the selection of the preferred first beam and / or the preferred third beam for said UE by the BS.

5. The method (100) of claim 4, wherein the generating of each of the one or more narrow beams by the BS (202) comprises: the BS (202) generating a sub-beam of the preferred first beam, the sub-beam having a coverage area that corresponds to the coverage area of the preferred third beam, or the BS (202) generating one of the second beams towards one of the DCSs and the said DCS generating a narrow beam that corresponds to the preferred third beam.

6. The method (100) of claim 5, wherein the generating of each of the one or more narrow beams by the BS (202) comprises the BS (202) generating the sub-beam of the preferred first beam if the performance metric of the preferred first beam exceeds that of the preferred third beam by a pre-defined threshold.

7. The method (100) of claim 5 or 6, wherein the generating of each of the one or more narrow beams by the BS (202) comprises the BS (202) generating one of the second beams towards one of the DCSs and the said DCS generating the narrow beam that corresponds to the preferred third beam, if the performance metric of the preferred first beam does not exceed that of the preferred third beam by a pre-defined threshold, or the feedback information comprises no information about the set of preferred first beams.

8. The method (100) of any of claims 1 to 7, wherein the transmitting of each of the one or more second signals via the one or more second beams towards the one or more DCSs by the BS (202) comprises: the BS (202) selecting one of the DCSs for generating one of the second beams towards said DCS based on pre-defined locations of the DCSs and the indexes or the coverage areas of the corresponding one or more first beams.

9. The method (100) of any of claims 1 to 8, further comprising the BS (202) providing each of the DCSs with an information about the indexes or the coverage areas of the one or more first beams.

10. The method (100) of any of claims 1 to 9, wherein each of the DCSs comprises subsets of controllable scattering elements and the generating of third signals by scattering one or more of the second signals impinging on the DCS comprises the DCS controlling phases of the scattering elements in each of the subsets to generate the third signals transmitted via the third beams.

11. The method (100) of claim 10, wherein the generating of third signals by scattering one or more of the second signals impinging on each of the DCSs comprises the DCS applying scattering patterns to its controllable scattering elements, wherein the scattering patterns are based on the indexes or the coverage areas of the one or more first beams that transmit the one or more first signals which are comprised as a part of the function in the impinging second signals.

12. The method (100) of claim 11, further comprising: the one or more DCSs receiving from the BS (202) a set of the unique codes for encoding the second signals into the third signals, and / or the one or more DCSs computing a set of the unique codes for encoding the second signals into the third signals based on the indexes or the coverage areas of the one or more first beams that transmit the one or more first signals which are comprised as a part of the function in the impinging second signals.

13. The method (100) of any of claims 1 to 12, wherein the unique codes for encoding the second signals into the third signals comprise frequency modulation codes or phase modulation codes.

14. The method (100) of any of claims 2 to 13, further comprising each of the UEs obtaining an information on the unique codes for decoding the third signals via a downlink control information from the BS (202) and / or using a pre-defined protocol.

15. The method (100) of claim 14, further comprising each of the UEs decoding the third signals and the corresponding one or more first signals received by the UE using the information on the unique codes.

16. The method (100) of any of claims 3 to 15, wherein the obtaining of performance metrics by each of the UEs comprises the UE measuring a signal strength and / or a signal to noise ratio for each of the received signals.

17. The method (100) of any of claims 3 to 16, further comprising, by each of the UEs: selecting a UE preferred first beam among the set of preferred first beams and a UE preferred third beam among the set of preferred third beams based on the performance metrics of the preferred first beams and the preferred third beams, setting a status flag to indicate if the performance metric of the UE preferred first beam exceeds that of the UE preferred third beam by a pre-defined threshold value, and adding the status flag into the feedback information.

18. The method (100) of any of claims 3 to 17, further comprising each of the UEs adding the performance metrics of the preferred first beams and the preferred third beams into the feedback information.

19. A Digitally Controllable Scatterer, DCS, assisted communication system, (100) comprising: a base station, BS, (202) configured for transmitting one or more first signals via one or more first beams within a set of first beams, wherein each first beam has a different index, a different direction and a different coverage area depending on an index of the first beam, andtransmitting one or more second signals via one or more second beams towards one or more Digitally Controllable Scatterers, DCSs, wherein each second beam is directed towards a different DCS, and each second signal is a function of the one or more first signals, wherein each of the DCSs is configured for generating third signals by scattering one or more of the second signals impinging on the DCS, wherein each third signal is a coded version of the impinging second signals encoded by the DCS with a unique code and transmitted via a third beam with a coverage area overlapping with a coverage area of the one or more first beams that transmit the one or more first signals comprised as a part of the function in the impinging second signals.

20. The system (200) of claim 19, wherein the BS (202) is further configured for: receiving a feedback information from one or more user equipment, UEs, about one or more of the first beams and / or one or more of the thirds beams, wherein the feedback information is computed by each of the one or more UEs based on the one or more first signals and / or the one or more third signals received by the UE, and generating one or more narrow beams for communicating with the one or more UEs, wherein each narrow beam comprises either a sub-beam of one of the first beams generated by the BS (202) or a beam generated by one of the DCSs that corresponds to one of the third beams, and each narrow beam is focused on one of the UEs based on the feedback information.

21. The system (200) of claim 20, wherein each of the UEs is configured for, in response to receiving one or more first signals via one or more first beams and one or more third signals via one or more third beams: obtaining performance metrics for the one or more first beams and the one or more third beams based on the received signals, selecting a set of preferred first beams and / or a set of preferred third beams, based on the performance metrics, and reporting to the BS (202) the feedback information comprising an information about the preferred first beam and / or the preferred third beam, and wherein the BS (202) is configured for selecting a preferred first beam and / or a preferred third beam from the set of preferred first beams and / or the set of preferred third beams for each of the UEs based on the feedback information reported by said UE.

22. The system (200) of claim 21, wherein the BS (202) is configured to focus each of the narrow beams on one of the UEs based on the selection of the preferred first beam and / or the preferred third beam for said UE.

23. The system (200) of claim 22, wherein the BS (202) is configured for generating each of the one or more narrow beams by means of: generating a sub-beam of the preferred first beam, the sub-beam having a coverage area that corresponds to the coverage area of the preferred third beam, or generating one of the second beams towards one of the DCSs, wherein the said DCS is configured for generating a narrow beam that corresponds to the preferred third beam in response to said second beam.

24. The system (200) of claim 23, wherein the BS (202) is configured for generating the sub-beam of the preferred first beam if the performance metric of the preferred first beam exceeds that of the preferred third beam by a pre-defined threshold.

25. The system (200) of claim 23 or 24, wherein the BS (202) is configured for generating one of the second beams towards one of the DCSs and the said DCS is configured for generating the narrow beam that corresponds to the preferred third beam, if the performance metric of the preferred first beam does not exceed that of the preferred third beam by a predefined threshold, or the feedback information comprises no information about the set of preferred first beams.

26. The system (200) of any of claims 19 to 25, wherein the BS (202) is configured for selecting one of the DCSs for generating one of the second beams towards said DCS based on pre-defined locations of the DCSs and the indexes or the coverage areas of the corresponding one or more first beams.

27. The system (200) of any of claims 19 to 26, wherein the BS (202) is configured for providing each of the DCSs with an information about the indexes or the coverage areas of the one or more first beams.

28. The system (200) of any of claims 19 to 27, wherein each of the DCSs comprises subsets of controllable scattering elements and is configured for controlling phases of thescattering elements in each of the subsets to generate the third signals transmitted via the third beams.

29. The system (200) of claim 28, wherein each of the DCSs is configured for applying scattering patterns to its controllable scattering elements, wherein the scattering patterns are based on the indexes or the coverage areas of the one or more first beams that transmit the one or more first signals comprised as a part of the function in the impinging second signals.

30. The system (200) of claim 29, wherein each of the DCSs is configured for: receiving from the BS (202) a set of the unique codes for encoding the second signals into the third signals, and / or computing a set of the unique codes for encoding the second signals into the third signals based on the indexes or the coverage areas of the one or more first beams that transmit the one or more first signals comprised as a part of the function in the impinging second signals.

31. The system (200) of any of claims 19 to 30, wherein the unique codes for encoding the second signals into the third signals comprise frequency modulation codes or phase modulation codes.

32. The system (200) of any of claims 20 to 31, wherein each of the UEs is configured for obtaining an information on the unique codes for decoding the third signals via a downlink control information from the BS (202) and / or using a pre-defined protocol.

33. The system (200) of claim 32, wherein each of the UEs is configured for decoding the third signals and the corresponding one or more first signals received by the UE using the information on the unique codes.

34. The system (200) of any of claims 21 to 33, wherein each of the UEs is configured for measuring a signal strength and / or a signal to noise ratio for each of the received signals to obtain the performance metrics.

35. The system (200) of any of claims 21 to 34, wherein each of the UEs is configured for: selecting a UE preferred first beam among the set of preferred first beams and a UE preferred third beam among the set of preferred third beams based on the performance metrics of the preferred first beams and the preferred third beams, setting a status flag to indicate if the performance metric of the UE preferred first beam exceeds that of the UE preferred third beam by a pre-defined threshold value, and adding the status flag into the feedback information.

36. The system (200) of any of claims 21 to 35, wherein each of the UEs is further configured for adding the performance metrics of the preferred first beams and the preferred third beams into the feedback information.

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