A scheduling method for integrated sensing and communication beamforming

Abstract

The present invention relates to a scheduling method for integrated sensing and communication beamforming. The present invention aims to provide a scheduling of communication users according to sensing needs of targets. The invention schedules the time-frequency resources of communication users to increase the ISAC beamforming while meeting the time-frequency resources requirement of sensing services.

Description

[0001] A SCHEDULING METHOD FOR INTEGRATED SENSING AND COMMUNICATION BEAMFORMING

[0002] TECHNICAL FIELD

[0003] The present invention relates to a scheduling method for integrated sensing and communication beamforming.

[0004] PRIOR ART

[0005] For the forthcoming era of advanced wireless networks, the role of 'sensing as a service' will become more crucial than ever. Recently, a new concept known as the 'perceptive network' has been introduced, which represents a significant shift in the way we think about providing both sensing and communications services concurrently. This innovative technology is commonly referred to as Integrated Sensing and Communications (ISAC).

[0006] There are three different beamforming types for ISAC in the literature: communication beamforming, sensing beamforming, and ISAC beamforming. The communication beamforming only serves for communication users, sensing beamforming serves for sensing targets, and ISAC beamforming serves for both communication users and sensing targets. ISAC beamforming is feasible only if communication user and sensing target are on the same beam. Since ISAC beamforming uses only one beam for both communication and sensing functionalities, it provides better energy efficiency and spectral efficiency. However, if communication user and sensing target are on different beams, the simultaneous signal transmission for sensing and communication by using the same time-frequency resources is feasible with generating separate beams. This is what is known in the literature. The way of increasing the probability of ISAC beamforming for a specific scenario is not known and has not been investigated in the literature. Although there are some scheduling methods for ISAC beamforming, there is not any scheduling method to increase the probability of ISAC beamforming.

[0007] Various aspects include systems and methods performed by base stations for scheduling. The studies in the literature schedule the sensing users for the beamforming design at the transmitter and investigate the joint scheduling for the periodic and aperiodic traffic.

[0008] The concept of 'sensing quality of service' for various applications, such as detection, localization, and tracking, has been introduced in reference document

[0001] . The authors in given reference document [1] have then developed a unified framework for the allocation of ISAC resources, considering fairness and comprehensive optimization criteria for these sensing services. These proposed methods offer the flexibility to allocate limited power and bandwidth resources based on the quality-of-service requirements for both sensing and communication. On the other hand, in the pursuit of achieving multiple functions simultaneously, emerging unified wireless systems like Integrated Localization and Communication (ILAC) and ISAC encounter a fundamental challenge of effectively allocating resources across coexisting functions and services. To address this challenge, an approach is introduced for an ILAC system that optimizes the allocation of shared hardware and radio resources for both localization and communication tasks in reference document [2], A novel concept called 'Value of Service' is introduced with the aim of maximizing the overall performance of the ILAC system, encompassing various service aspects such as localization accuracy and communication data rates in reference document [2], Additionally, the problem of allocating bandwidth and temporal resources in the context of ILAC is formulated to maximize its value of service.

[0009] The literature has examined the concept of transmit beamforming in a downlink ISAC system in reference document [3]. In this system, a base station employs a uniform linear array to simultaneously transmit a combination of information-bearing data and dedicated radar signals. This setup serves the dual purpose of facilitating multiuser communication and radar target sensing. The study explores two distinct radar sensing design criteria: the conventional approach of matching the sensing beam pattern and a novel approach known as minimum weighted beam pattern gain maximization. Within this framework, the primary objective is to optimize radar sensing performance while ensuring that each communication user meets their individual signal-to- interference-plus-noise ratio (SINR) requirements, all while adhering to the base station's maximum transmit power constraints. The study of given references document [4] centers around an ISAC-enabled system operating in the context of Ultra-Reliable Low-Latency Communications (URLLC). Specifically, it deals with the scenario where sporadic traffic is triggered by specific events and competes for wireless channel resources alongside regularly occurring traffic. Meeting the stringent demands for low latency and high reliability in URLLC necessitates an efficient traffic scheduling strategy that leverages the results of event sensing. Concurrently, the system employs an ISAC design to simultaneously sense the target and transmit traffic. Consequently, both the formation of ISAC signals and the scheduling of traffic have a significant impact on the overall performance in terms of latency and reliability for both types of traffic - periodic and sporadic. As a response to this challenge, the study proposes a unified approach to the design of ISAC beamforming and traffic scheduling. This is a departure from the prevailing approach in the field, which tends to focus on separate designs. Our overarching goal is to maximize the likelihood of successful transmission for both types of traffic within strict deadline constraints, thereby meeting the rigorous quality of service requirements inherent in URLLC.

[0010] The study of given reference document [5] introduces a scheduling approach for the Non-Orthogonal Multiplexing Access (NOMA)-aided ISAC system. In this paradigm, the ISAC base station concurrently serves a cluster of users through NOMA for data transmissions and carries out multi-target sensing for a group of sensing targets. The key consideration is ensuring that each NOMA user receives the necessary amount of data within a specified time frame. To evaluate the effectiveness of multi-target sensing, the study adopts the concept of sensing estimation mutual information and guarantees that ISAC base station echoes of sensing targets which are scheduled to be sensed. This approach frames a comprehensive optimization problem that encompasses beamforming, the duration of NOMA transmissions, and the sensing scheduling with the objective of maximizing the sensing efficiency of the system.

[0011] In another technical problem, if Communication User (CU) and Sensing User (SU) / Sensing target (ST) are on the same beam, ISAC beamforming can be used (known in the literature). However, how to schedule the resources of CU and SU / ST in the time frequency frame is not known and investigated in literature. There is no study for scheduling sensing and communication users to increase the probability of ISAC beamforming.

[0012] In the 5G network, Resource Allocation (RB allocation) / TTI needs measurement (UE / NETWORK), BSR (BUFFER STATUS REPORT) QoS Requirement, associated radio bearer and SR (Scheduling Request) information in scheduler. However, this information is not applicable for 6G network.

[0013] All the problems mentioned above have made it necessary to make an innovation in the relevant technical field as a result.

[0014] BRIEF DESCRIPTION OF THE INVENTION

[0015] The present invention relates to scheduling method to eliminate the above-mentioned disadvantages and bring new advantages to the relevant technical field.

[0016] In the first aspect, the embodiment of the present application provides a scheduling method, which can be executed by a network device, or by a component of the network device (such as a processor, a chip, or a chip system, etc.), or can be implemented by all or logical modules or software implementations of some network device functions or computer implemented device.

[0017] The main object of the invention is to provide a scheduling of communication users according to sensing needs of targets. The invention schedules the time-frequency resources of communication users to increase the ISAC beamforming while meeting the time-frequency resources requirement of sensing services.

[0018] One another aspect of the invention also provides a service to both sensing and communication users in one beam.

[0019] Through this method that makes it possible to;

[0020] • Increase the probability of ISAC beamforming in the system with a proper scheduling of the time and frequency resources of communication users. • Provide more energy efficient due to single beam for CU and SU / ST. For instance, in cases where 2 beams should be used, energy efficiency is provided by using a single beam. In this way, 50 percent gain in energy efficiency is achieved,

[0021] • Decrease the number of beams needed in comparison to the methods known in the prior art,

[0022] • Using of more capacity due to having more beam for communication. For instance, we assume that is sent ten beams from the base station. Thanks to invention, all beams can be used for communication. However, if there is only sensing application, five of ten beams are used for communication and other beams for sensing. Scenario can be more not only limited to this example.

[0023] The scheduling method proposed by the embodiment of the present application can be applied to the 6G or similar networks.

[0024] To achieve all the objects mentioned above and that will emerge from the following detailed description, the present invention relates to a scheduling method for integrated sensing and communication beamforming.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present disclosure, in accordance with one or more various examples, is described in detail with reference to the following figures. The drawings are provided for purposes of illustration only and merely depict examples of the disclosure. These drawings are provided to facilitate the reader's understanding of the disclosure and should not be considered limiting the breadth, scope, or applicability of the disclosure. It should be noted that for clarity and ease of illustration these drawings are not necessarily made to scale.

[0027] Figure 1 : The types of ISAC beamforming.

[0028] Figure 2: The time-frequency domain resource scheduling for multiple communication users.

[0029] Figure 3: The time-frequency domain resource scheduling for multiple sensing targets. Figure 4: The proposed time-frequency domain resource scheduling for multiple communication users and sensing targets.

[0030] Figure 5: The flow diagram of the proposed scheduling method.

[0031] Figure 6: Conventional and proposed scheduling method diagrams.

[0032] REFERENCE LIST

[0033] The reference numbers of the elements included in the figures are explained below.

[0034] 101 Transceiver

[0035] 102 Communication beamforming

[0036] 103 Sensing beamforming

[0037] 104 ISAC beamforming

[0038] 105 Communication user

[0039] 106 Sensing target

[0040] 201 Minimum schedulable slot

[0041] 202 The time-frequency resources of first communication user

[0042] 203 The time-frequency resources of second communication user

[0043] 204 The time-frequency resources of A / -th communication user

[0044] 302 The time-frequency resources of first sensing target

[0045] 303 The time-frequency resources of second sensing target

[0046] 304 The time-frequency resources of M-th sensing target

[0047] 402 The time-frequency resources of first communication user

[0048] 403 The time-frequency resources of second communication user

[0049] 404 The time-frequency resources of A / -th communication user

[0050] 601 Conventional scheduling

[0051] 602 Proposed scheduling

[0052] 603 First CU’s slot

[0053] 604 Second CU’s slot

[0054] 605 First ST’s slot

[0055] 606 Second ST’s slot

[0056] 607 Beam

[0057] 608 First CU

[0058] 609 Second CU 610 First ST

[0059] 61 1 Second ST

[0060] DETAILED DESCRIPTION OF THE INVENTION

[0061] In this detailed description, the subject matter is explained with references to examples without forming any restrictive effect only to make the subject more understandable.

[0062] The invention relates to a scheduling method for integrated sensing and communication (ISAC) beamforming which is shown in figure 5.

[0063] The proposed scheduling method schedules the time-frequency resources of the communication users according to the time-frequency resources of the targets and the target beams.

[0064] The proposed scheduling method is dependent on computer implemented method. The method can implement by a processor of network device for integrated sensing and communication beamforming wherein the method comprises, scheduling the timefrequency resources of the communication users according to the time-frequency resources of the targets and the target beams in the environment which is comprising at least one communication user (105), at least one sensing target (106) and at least one transceiver (101 ).

[0065] The scheduling method comprises the following steps:

[0066] • Generating sensing / radar and communication signals and receives the reflected signals from the at least one target in the environment for detection signals by the at least one transceiver (101 ),

[0067] • Obtaining beam information from detected signals to know which user is in which beam, which target is in which beam for all communication users and targets in the environment by the transceiver (101 ),

[0068] • Deploying time-frequency resource allocation independently for communication users and targets for scheduling by transceiver (101 ), • Matching (scheduling of communication users is according to target resources to overlap) communication users and targets if they are on the same beam for scheduling,

[0069] • Allocating the communication users resources on the target resources on the same beam for scheduling,

[0070] • Transmitting the integrated sensing and communications signal on the same beam for energy efficiency.

[0071] The invention provides to increase the probability of ISAC beamforming in the system with a proper scheduling of the time and frequency resources of communication users. This scheduling meets the time-frequency resource requirements for sensing accuracy.

[0072] ISAC beamforming is the most energy and spectral efficient way. Thanks to ISAC beamforming, joint communication and sensing signaling is transmitted on a single beam. The invention schedules the time-frequency resources of communication users to increase the ISAC beamforming while meeting the time-frequency resources requirement of sensing services.

[0073] When the scheduling of communication users is adjusted, the less beams are used in the communication technique. In this way, there is no need to use communication beam and sensing beam separately.

[0074] Through the method in invention, it is possible to increase the probability of using the same beam for sensing and communication.

[0075] The system model of integrated sensing and communication (ISAC) transceiver is represented in Figure 1. The system model consists of a multi-input multi-output (MIMO) transceiver (101 ), communication beamforming (102), sensing beamforming (103), ISAC beamforming (104), communication user (105), and sensing target (106). The transceiver (101 ) generates sensing / radar and communication signals and receives the reflected signals from the targets (106) in the environment. In the conventional communication systems, communication beamforming (102) is done to transmit data for high-quality communication services. The sensing targets (106) can be sensed thanks to sensing beamforming (103) where the signal on the beam does not carry data. The sensing targets (106) can be active and passive. Passive sensing targets (106) only reflect the signal and do not make signal reception. Active sensing targets (106) receive the transmitted signal and make the sensing at the sensing targets (106). On the other hand, if a target (106) or communication user (105) requests sensing and communication functions simultaneously on the same beam, an ISAC beamforming (104) is generated where the transmitted signal on the beam is used for data transmission and sensing. Therefore, the transmitted signal carries data and requires to be modified for meeting sensing and communication requirements satisfactorily at the same time. If a communication user (105) requests data transmission and there is no target (106) to be sensed on the beam, communication beamforming (102) is required. If a target (106) is needed to be sensed and there is not any communication user (105) on the beam, sensing beamforming (103) is required. If a communication user (105) requests data transmission and there is a target (106) to be sensed on the beam, ISAC beamforming (104) is required. Therefore, ISAC beamforming (104) has better energy efficiency and more capacity compared to other beamforming types to meet sensing and communication requirements satisfactorily due to the use of the same signaling on one beam for both requirements.

[0076] In 5G New Radio, a radio frame consists of 10 subframes and a subframe consists of 10 slots. Slots with a normal cyclic prefix (CP) always contain 14 symbols, while slots with an extended CP always contain 12 symbols. Moreover, the accommodation for the physical properties of different numerologies is achieved by varying the number of slots within one subframe. In the frequency domain, a resource block has 12 subcarriers. Therefore, the time-domain resources of this frame are shared among multiple users according to the determined slot formats. Here, the frame duration is 10 milliseconds (ms). Like 5G NR, Figure 2 represents the radio frame of a communication system. The total number of communication users is considered as N. It consists of a minimum schedulable slot (201 ) (Minimum schedulable slot can be different values for CU, SU, and CU&SU.), the time-frequency resources of first communication user (202), the time-frequency resources of second communication user (203), and the time-frequency resources of A / -th communication user (204) where the slot has the modulated data symbols. Although the users have the same amount of the timefrequency resources as shown in the figure, they may have different amounts of the time-frequency resources. The resource allocation of users is done according to their channel conditions and packet sizes in conventional communication systems. Therefore, the size and distribution of user resources can be different from each other. If there is not any sensing target (106) in the system, communication beamforming (102) is deployed by the MIMO transceiver (101 ) for communication users (105).

[0077] To sense the targets, the MIMO transceiver (101 ) requires a transmitting sensing signal. Therefore, the time-frequency resources to meet sensing requirements like range and velocity resolutions and range and velocity range intervals must be allocated for the sensing signal. Since sensing is generally required to be tracked, the sensing signal is transmitted periodically for the applications. Figure 3 represents the radio frame of a sensing system. The total number of sensing targets (106) is considered as M. It consists of a minimum schedulable slot (201 ), the time-frequency resources of first sensing target (302), the time-frequency resources of second sensing target (303), and the time-frequency resources of M-th sensing target (304) where the slot has the unmodulated symbols for sensing. If there is no any communication user (105) in the system, sensing beamforming (103) is deployed by the preferably MIMO transceiver (101 ) for sensing targets (106).

[0078] In conventional communication systems, the time-domain resources are scheduled for A / users as shown in Figure 2. On the other hand, for sensing functionalities, the timedomain resources are scheduled for M targets as shown in Figure 3. If joint communication and sensing is required in the system, the sensing and communication signals are transmitted by generating different beams. If a user and target are on the same beam, a one beam can serve them. Otherwise, different beams are generated for the user and communication user with considering the use of same time-frequency resources. The proposed scheduling method increases the probability of existence of targets and users on the same beam. Let’s assume that the n-th communication user (n=1, 2,...,N) and the m-th target are on the same beam if n=m. For instance, the first communication user and the first target are on the same beam according to this assumption. Therefore, the same beam is used for the first communication user and target. However, this is only feasible if they are allocated on the same time-frequency resources. Therefore, the time-frequency resources for the A / communication users are scheduled as shown in Figure 4. It consists of a minimum schedulable slot (201 ), the time-frequency resources of first communication user (402), the time-frequency resources of second communication user (403), and the timefrequency resources of A / -th communication user (404) where the slot have the modified data symbols or joint data symbols and sensing signal. For the modified data symbols case, the modulated data symbols are modified to meet the sensing and communication simultaneously by using the same waveform. On the other hand, for the joint data symbols and sensing signal, two different waveforms are used to meet the sensing and communication simultaneously by using the same time and frequency resources. These two waveforms can be combined orthogonally or non-orthogonally. The proposed scheduling method schedules the time-frequency resources of the communication users according to the time-frequency resources of the targets and the target beams. The proposed method does not guarantee the same time-frequency allocation for sensing and communication to transmit on the same beam; however, it increases the probability of using the same beam for sensing and communication.

[0079] The flow diagram of the proposed scheduler is given in Figure 5. Firstly, the transceiver (101 ) obtains beam information for A / communication users and M targets (501 ). In conventional beam training procedures, the beam information of the users can be obtained, and the beam information for the targets can be obtained with target detection methods before signal transmission. Also, resource requirement for the communication resources for users and targets, and sensing periodicity are required at the transceiver (101 ). The resolution and range for sensing depend on the allocated resources on the frame; therefore, the time-frequency resources must be determined to meet the resolution and range requirement for the targets. Secondly, the timefrequency resources are scheduled independently for users and targets, and the frames in Figures 2 and 3 are obtained. These frames are scheduled independently to meet communication and sensing requirements. If communication and sensing is multiplexed in the spatial domain by using multiple antenna structure, these two frames can be transmitted simultaneously. If the resources of targets and users are on different beams, different beams are used. On the other hand, if the resources of targets and users are on the same beams, the same beam is used. Here, the time-frequency resources of the n-th communication user and the m-th target are denoted by Rc nand Rs m, respectively. Therefore, RC 1and RS 1are denoted in Figure 2 and figure 3 with the time-frequency resources of first communication user (202) and the time-frequency resources of first sensing target (302), respectively. Although, the size of RC Nand RS Mare described equal in the figures, they may have different sizes from each other. Thirdly, match N communication users and M targets considering their beam information. The system have ^different beam configuration (k=1, 2,...,K). Therefore, the transceiver finds the n-th user and m-th target on the k-th beam. For instance, the users with n=1 ,2 and the target with m=1 are on the same beam k=1. Here, for simplicity, it is considered that if n=m, user and target is on the same beam. Fourthly, the target resources (7?s jn) are allocated for the communication users, then R_(c,m) = R_(s,m) (505). In this way, the sensing requirements will be met as shown in Figure 4. Note that the modulated data symbols are allocated on Rs m. Therefore, the only user allocation in the frame is changed compared to conventional communication frame. Thanks to this scheduling, ISAC beamforming applied for the n-th communication user and m-th target on the k-th beam. This decreases the total number of beamforming in the system. Moreover, since more beams will be available for communication, the capacity will also increase. If this proposed scheduling is not done, more beamforming is required to be generated for communication and sensing as in done for conventional systems.

[0080] To explain the proposed scheduling method better, a simple example is illustrated in Figure 6. Communication user (105) and sensing target (106) is abbreviated as CU and ST, respectively. The figure consists of a MIMO transceiver with conventional scheduling (601 ), a MIMO transceiver with proposed scheduling (602), first CU’s slot (603), second CU’s slot (604), first ST’s slot (605), second ST’s slot (606), a beam (607), first CU (608), second CU (609), first ST (610), and second ST (61 1 ). As seen from the figure, CU 1 - ST 2 and CU 2 - ST 1 are considered that they exist on the same beam coverage. For the frame duration, four slots with a fixed band are considered. The time-frequency resources are scheduled as shown in the figure without proposed scheduling (602). For the first slot, since CU 1 and ST 1 are under coverage of different beams, two different beams with communication and sensing beamforming are generated. For the second slot, since CU 1 and ST 2 are under coverage of same beam, one beam with ISAC beamforming is generated. Therefore, for the four slots, six beams are generated for the conventional scheduling. On the other hand, the proposed scheduling arranges the CU resources according to the required ST resources. Since CU 1 - ST 2 and CU 2 - ST 1 are on the same beam, the proposed scheduling is done as described in the figure. In this case, CU and ST are on the same beam for all slots so that only ISAC beamforming is used for all slots. Therefore, four beams are generated for the four slots in the proposed scheduling. As deduced from this example, the proposed scheduling increases the probability of ISAC beamforming and decreases the total number of beams generated at the transceiver for CUs and STs.

[0081] In the 5G, there is a need for some information in scheduler for instance Resource Allocation (RB allocation) / TTI, measurement (UE / NETWORK), BSR (BUFFER STATUS REPORT) QoS Requirement, associated radio bearer and SR (Scheduling Request). However, this information is not enough to scheduling. In 6G, results for SU, sensing periodicity and beam information is used for resource allocation in scheduler.

[0082] Based on consideration of the foregoing technical solution, possible embodiments of the invention are as follows;

[0083] • The method wherein said transceiver (101 ) is a multi-input multi-output transceiver.

[0084] • The method wherein said transceiver (101 ) is a base station.

[0085] • The said method schedules the time-frequency resources of the communication users according to the time-frequency resources of the targets and the target beams.

[0086] • Resource allocation or scheduling algorithm is used for both sensing and communication in the deploying step.

[0087] • Targets are active targets or passive targets while sensing process.

[0088] • Measurement result for sensing user, sensing periodicity and beam information is used for resource allocation. References:

[0089]

[0001] F. Dong, F. Liu, Y. Cui, W. Wang, K. Han and Z. Wang, "Sensing as a Service in 6G Perceptive Networks: A Unified Framework for ISAC Resource Allocation," IEEE Transactions on Wireless Communications, vol. 22, no. 5, pp. 3522-3536, May 2023.

[0090] [2] Li, Biwei, et al. "Value of Service Maximization in Integrated Localization and Communication System through Joint Resource Allocation," IEEE Transactions on Communications, vol. 71 , no. 8, pp. 4957-4971 , May 2023.

[0091] [3] H. Hua, J. Xu and T. X. Han, "Optimal Transmit Beamforming for Integrated Sensing and Communication,” IEEE Transactions on Vehicular Technology, vol. 72, no. 8, pp. 10588-10603, Aug. 2023.

[0092] [4] X. Zhao and Y. -J. A. Zhang, "Joint Beamforming and Scheduling for Integrated Sensing and Communication Systems in URLLC," GLOBECOM 2022 - 2022 IEEE Global Communications Conference, Rio de Janeiro, Brazil, 2022, pp. 3611 -3616.

[0093] [5] C. Dou, N. Huang, Y. Wu, L. Qian and T. Q. S. Quek, "Sensing-Efficient NOMA- Aided Integrated Sensing and Communication: A Joint Sensing Scheduling and Beamforming Optimization," IEEE Transactions on Vehicular Technology, doi: 10.1109 / TVT.2023.3277734.

Claims

CLAIMS1. A computer implemented scheduling method for integrated sensing and communication beamforming wherein the method comprises, scheduling the time-frequency resources of the communication users according to the timefrequency resources of the targets and the target beams in the environment which is comprising at least one communication user (105), at least one sensing target (106) and at least one transceiver (101 ).

2. The scheduling method according to claim 1 , characterized in that comprising the following steps:• Generating sensing / radar and communication signals and receives the reflected signals from the at least one target in the environment for detection by the at least one transceiver (101 ),• Obtaining beam information from detected signals to know which user is in which beam, which target is in which beam for all communication users and targets in the environment by the transceiver (101 ),• Deploying time-frequency resource allocation independently for communication users and targets for scheduling by transceiver (101 ),• Matching communication users and targets if they are on the same beam for scheduling,• Allocating the communication users resources on the target resources on the same beam for scheduling,• Transmitting the integrated sensing and communications signal on the same beam for energy efficiency.

3. The method of according to claim 1 or claim 2, wherein said transceiver (101 ) is a multi-input multi-output transceiver.

4. The method of according to claim 1 or claim 2, wherein said transceiver (101 ) is a base station.

5. The method of according to claim 2, wherein the said method schedules the time-frequency resources of the communication users according to the timefrequency resources of the targets and the target beams.

6. The method of according to claim 2, wherein said resource allocation or scheduling algorithm is used for both sensing and communication in the deploying step.

7. The method of according to claim 1 or claim 2, wherein said targets are active targets or passive targets while sensing process.

8. The method according to claim 2, wherein measurement results for sensing users, sensing periodicity and beam information are used for resource allocation.

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