Method and system for inactive and active beam transitions in a satellite radio access network - Patents.com

Abstract

A satellite radio access network includes base stations for communicating with standard-compliant user equipment (UE) via satellites having a field of view. A network broadcasting signal is provided via an inactive or access beam covering multiple cells within the field of view. An access request is detected from a user equipment, such as a smartphone, in an area covered by the inactive beam. In response to the access request, the beam transitions from inactive to active to provide network access to the user equipment. When the user device goes out of range, the active beam transitions back to the inactive beam. An inactivity timer is used to detect an idle active cell that should transition to an inactive cell.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 292,914, filed December 22, 2021, which is incorporated by reference herein as if filed in its entirety.

[0002] Technical Field The present disclosure relates to satellite radio access, and more particularly to a hybrid approach to resource management in a satellite radio access network by balancing inactive and active cells on a satellite using modified GSM base stations to enable direct satellite communication for unmodified GSM devices. [Background technology]

[0003] As telecommunications advances, governments and regulators in many countries are demanding that new operators cover 100% of the country's territory, including areas with low demand where the cost is difficult to justify. Such a requirement has put several Mobile Network Operators (MNOs) in a bind, as providing full coverage with 3GPP RAN systems may be too expensive. There is therefore a need in the art to provide a solution for resource management of the SAtRAN (Radio Access Network) that allows SAtRAN access to regular smartphones in remote areas where TN coverage is not reached (e.g., 0G areas). Summary of the Invention

[0004] The present embodiment may particularly relate to a system and method for providing a satellite network that allows coverage of a normal smartphone (i.e., a standard GSM phone that typically communicates via 3GPP and is not modified or specially adapted to communicate via a satellite, e.g., a non-satellite phone) without requiring modification to the normal smartphone. In some embodiments of the present disclosure, the satellite network provides coverage to normal smartphones in remote areas, such as areas not covered by terrestrial cellular networks (mobile phone networks, e.g., GSM networks). In some embodiments of the present disclosure, the Satellite Radio Access Network (SatRAN) turns a normal smartphone into a satellite phone without modification to the smartphone. The prior application disclosure (US11,121,764) uses LTE 1.4 Mhz cell bandwidth. In the disclosed technology, GSM is added for cells with wider inactive access beams. When a RACH (Random Access CHannel) is received, the inactive wide beam is changed to an active spot beam. Depending on the services required, some embodiments provide handover to a newly served LTE beam or continue to use the same GSM cell for voice calls. [Brief description of the drawings]

[0005] These accompanying drawings are incorporated in and constitute a part of this specification. It should be understood that these drawings show only some embodiments of the present disclosure, and other embodiments or combinations of various embodiments not specifically shown in the drawings may still fall within the scope of the present disclosure. Next, the embodiments will be described in more detail with reference to the drawings.

[0006] [Figure 1]FIG. 1 illustrates a satellite system in accordance with one or more embodiments of the present disclosure.

[0007] [Figure 2A] FIG. 2A illustrates an example of a satellite system implementation of a hybrid approach for satellite radio access, in accordance with one or more embodiments of the present disclosure.

[0008] [Figure 2B] FIG. 2B illustrates an example of a hybrid approach for satellite wireless access implemented in a satellite system in accordance with one or more embodiments of the present disclosure, showing an inactive wide beam that is many times larger than the active spot beam.

[0009] [Diagram 3] 3A-3C show examples of pre-defined active cells and cell groups for a wide area, in accordance with one or more embodiments of the present disclosure.

[0010] [Figure 4A] FIG. 4A illustrates a diagram 400 of resource management for a SatRAN system in accordance with one or more embodiments of the present disclosure.

[0011] [Figure 4B] FIG. 4B illustrates an example of a cell cluster, in accordance with one or more embodiments of the present disclosure. [Figure 4C] FIG. 4C illustrates an example of a cell cluster, in accordance with one or more embodiments of the present disclosure.

[0012] [Diagram 5] FIG. 5 illustrates an example block diagram 500 of a computing device in accordance with one or more embodiments of the present disclosure.

[0013] These figures depict exemplary embodiments of the present disclosure. Other embodiments may include components of different scales. The same numbers used in the figures may be used to refer to the same components. However, the same numbers used to refer to a component or step in a given figure have the same structure or function when used in another figure labeled with the same number, unless otherwise noted. DETAILED DESCRIPTION

[0014] In describing the exemplary, non-limiting embodiments illustrated in these drawings, specific terms are used for clarity. However, it is to be understood that the disclosure is not intended to be limited to the specific terms so selected, and that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. Although several embodiments have been described for purposes of illustration, it is understood that the present specification and claims are not limited to the illustrated embodiments, and that other embodiments not specifically shown in these drawings may be within the scope of the disclosure.

[0015] In accordance with one or more embodiments, the disclosed technology addresses the desire to provide a Satellite Radio Access Network (SatRAN) that provides global communications services to regular smartphones in uncovered or underserved areas, wherever the smartphones are, at a cost similar to existing Terrestrial Networks (TNs). For example, using SatRAN, regular smartphones can be served in mountains, deserts, oceans, and remote uninhabited areas. In some embodiments, SatRANs can help solve the digital divide problem (also known as the 0G problem) in areas where networks are not covered (unserviced areas).

[0016] According to one or more embodiments, the disclosed technology provides benefits to all smartphone users by solving the 0G problem on a global scale. For example, the disclosed technology may provide a satellite network and modified base stations (e.g., 2G / 4G / 5G base stations) to provide communication services (area served, communication area, reception area, coverage) formed from the satellite network. In some embodiments, the disclosed technology may enable 3GPP RAN from space without relying on ground-based towers (terrestrial base stations). It may also help mature markets in developed countries that have a few percent blind spots. For example, 2% of the UK is 0G. In general, SatRAN can provide communication services in remote areas as easily as in town centers. However, because there is not as much demand in remote areas, it is ideal for communication services in remote areas to avoid using too many SatRAN resources that may be needed elsewhere in the satellite's field of view (FoV).

[0017] According to one or more embodiments, the disclosed technology may include introducing inactive cells of SatGSM (satellite GSM) to handle providing network access to smartphones on demand. In some embodiments, for such cases, the requested communication service (coverage) can be provided without extra capital expenditure (CapEx) and with less than 1% operational expense (OpEx). GSM only requires 200 kHz to provide communication service (coverage) to remote areas, and it can be applied if there is demand for the appropriate RAT, bandwidth, and service. Using GSM as an access cell is fundamentally different from LTE, which are two different types of RAT. GSM is narrowband at the same power level as LTE, so it has a much better chance of reception than a wideband signal (4G). In addition, GSM also has 7 dB more maximum Tx power. GSM starts with the maximum power of RACH, whereas LTE starts with a lower power. According to one or more embodiments, the disclosed technology can provide GSM access via low-orbit satellites. Satellite GSM can provide GSM only at 200 kHz and 30 dbm power. LTE has a maximum of 23dbm. GSM therefore offers high power concentrated within 200kHz. In contrast, LTE is wideband, spread out and weak, making it easier to receive the RACH in SatGSM.

[0018] Currently, satellite phones are the only solution for remote areas with little access to cellular networks (e.g. 0G). However, satellite phones are not only much more expensive than smartphones, but also have far fewer features than regular smartphones (e.g. GSM mobile phones). It would be beneficial to provide communication services (coverage) using a network of satellites, turning a regular smartphone into a satellite phone without any modifications to the smartphone.

[0019] In the following description, for purposes of explanation, numerous specific details are set forth in order to fully understand the disclosed concepts. As part of this description, some of the drawings of the present disclosure represent structures and devices in block diagram form to avoid obscuring the novel aspects of the disclosed embodiments. In this context, reference to a numbered drawing element (e.g., 100) without an associated identifier refers to all instances of the drawing element with the identifier (e.g., 100a and 100b). Additionally, as part of this specification, some of the drawings of the present disclosure may be provided in the form of a flow chart. The boxes of any flow chart may be presented in a particular order. However, the particular flow of any flow chart is used only to illustrate one embodiment. In other embodiments, any of the various components depicted in the flow chart may be omitted, or the components may be performed in a different order or simultaneously. In addition, other embodiments may include additional steps not depicted as part of the flow chart. The language used in this disclosure has been selected primarily for ease of reading and explanation, and may not have been selected to define or encompass the disclosed subject matter. In this disclosure, "one embodiment" or "one particular embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment, and multiple references to "one embodiment" or "one particular embodiment" should not necessarily be understood as all referring to the same embodiment or to different embodiments.

[0020] It should be understood that in the development of any actual implementation (as in any development project), numerous decisions (e.g., system compliance and business-related constraints) must be made to achieve the developer's particular goals, and that these goals will vary from implementation to implementation, and that such development efforts may be complex and time-consuming, but will nevertheless be routine for one of ordinary skill in the art of image capture having the benefit of this disclosure.

[0021] In the disclosed technology, one or more embodiments are described that provide solutions to current problems experienced by remote locations with respect to cellular network coverage, including but not limited to A) provisioning costs, B) low demand, and C) working assumptions of 3GPP specifications.

[0022] A: Cost of delivery: It is difficult for network operators to provide RAN services in remote areas because they lack the infrastructure and electricity to run radio equipment. They also often lack effective protection for the equipment. And in large, remote areas, as is often the case in impoverished regions like Africa, there are often not enough skilled personnel to support, own and maintain RAN technology.

[0023] B: Low Demand Issues: Even if supply costs are not an issue, if demand is low in any area, it is difficult to justify the investment in both capital and operational costs. This is often the case in developed and developing countries. However, there is a critical need for such communication services (coverage), for example to enable emergency calling.

[0024] C: Problems with the working assumptions of 3GPP specifications: 3GPP specifications are designed for a global mass market, not for personal use in remote locations where mobile services are not needed most of the time. As communication technology advances worldwide, corner cases such as coverage issues become a hot topic. Mobile device users have become accustomed to the convenience of their mobile devices and assume that cellular networks will be available wherever they venture.

[0025] In some embodiments, problems related to providing may be solved by the disclosed technology. A satellite RAN requires a ground station, such as a data center, which may be far away from the cell that the satellite RAN actually serves. For example, the ground station may be 1,000 km away (e.g., on the edge of a city) and cover a large area of ​​land. For example, a satellite RAN as described herein may cover a large portion of a country, if not the entire country.

[0026] In some embodiments, the low demand problem may be solved by the disclosed technology. For example, inactive wide beams of GSM spot beams for satellite cells may be used to lower OpEx (operational costs) between solar power generation and feeder links. Additionally or instead, a larger area may be covered by using GSM cells as access cells with less (e.g., 1 / 7) of the feeder link bandwidth of the smallest LTE cell. Also, it is much easier to install GSM RACH detectors on the satellites, which can further aid in efficient RACH detection for the accuracy of each spot beam without consuming feeder link bandwidth in the inactive state, which may be up to 99.9% of the time in large inactive cell areas. This is a unique advantage of satellite RAN. Such technology disclosed herein allows satellite RAN technology to cover oceans with little additional cost, ideally providing global coverage even over the ocean. This may further reduce the concern of the low demand problem. Additionally, it can improve preemptive random access response (RAR) in LTE DL. In addition to beam handover, delay compensation, and Doppler compensation, this is another technical improvement for satellite RAN resource management, and a major difference from cell handling from the Terrestrial network (TN).

[0027] In some embodiments of the disclosed technology, the satellite RAN ground station may have a database for storing and maintaining cell locations. This database may be accessed by redundant multi-RAT (e.g., 2G, 4G, 5G), BTS, eNB(s), and gNB(s) of various cell bandwidths. Each may have various cell bandwidths and various capacities that are on standby to provide services. These system information and core network parameters may be dynamically changed according to the needs of network users. In contrast, multiple TNs are usually initialized and do not need to be changed. Therefore, they waste a lot of power at night when services are less needed. Therefore, with the satellite RAN disclosed in this case, the TN also benefits from saving OpEx. (In 2012, the electricity cost of the global RAN was $500 million.)

[0028] An inactive cell is a state of a cell that is not currently in use (e.g., no user equipment is using voice or data services) but is ready to serve a potential user by becoming an active cell. An active cell is a state of a cell that is currently in use (e.g., at least one voice or data call is in progress). In the disclosed technology, an inactive cell has one major difference from an active normal cell, which is that it can expand (expand) to many times the size of a normal cell. That is, a normal cell has a narrow beam width or is a spot (e.g., about 48 km in low bands below 1 GHz), and the cell size does not change much (does not change much) until it becomes an inactive cell. An inactive cell mainly functions as an access cell, and is preferably as large as possible to spread over a wide area (e.g., ocean) where there is usually little demand for services. With extended TA, GSM can expand to a cell radius of 120 km or more, but there is no need to impose any restrictions on inactive beams / cells because their function is only to detect RACH. Therefore, the TA range restriction does not apply. The range of the TA only concerns the active spot beam that takes over the user traffic at the time the RACH is detected, which is functional from the moment of the RACH response.

[0029] Many TN cells are idle during the night, but this is generally short, lasting no more than a few hours at night. Therefore, no one would consider putting special states in eNBs, gNBs, or BTSs. However, this disclosure may be used to save power and reduce operational costs.

[0030] Along the same concept, on-demand resource allocation is possible, which is crucial for satellite RAN. In some embodiments, solar power and feeder links, as well as the operational performance of the satellite hardware, are better used to serve people and practical applications within the thousands of square kilometers served by the satellite. If there are no or few user equipments (UEs) using the resources and capabilities, it is better to use GSM since it has the lowest cost for bandwidth per unit area. Spectrum (frequency bands) may be provided in a balanced manner with solar power and providing communication services to other cells that have more demand most of the time. A simple calculation can show the resource ratio with a normal TN cell in a densely populated area. For example, the spectrum saving rate of TN deployment and satellite RAN can be compared and calculated. Further improvements may be made to justify the provision of global communication services (global coverage) of satellite RAN. A normal TN deployment (placement) is 20MHxCBW2T2R (200MHx CBW 2T2R) per square km. The deployment of a satellite RAN to provide communication services (coverage) to distant (ocean) areas as inactive cells is 200 kHz 1T1R (200 kHz 1T1R) for an area of ​​3000 square km, with a resource factor of 1 / 8 and a factor of 8. The area factor is (3000 / 1 =) 3000 and the frequency BW factor is (20e6x2 / 200e3 =) 200. The total factor of spectrum (frequency, frequency band) resources saved compared to a terrestrial TN deployment is (3000 x 200 x 8 =) 4.8 million. The importance increases the larger the area covered. A satellite in low Earth orbit (LEO) may serve an area of, for example, 2800 km in diameter, which becomes a key part of the system design. While the transition between inactive and active beams avoids large resource waste, the general resource management scheme described herein may optimize the entire system for better performance and efficiency. Given the scale of a satellite RAN, this situation is very significant and may require special design work to handle it appropriately.

[0031] Some embodiments of the disclosed technology may balance the use of satellite RAN resources between inactive and active cells, which may include, but are not limited to, each satellite's valuable feeder link bandwidth and the solar power available on those satellites.

[0032] Further technological developments will be provided to address resource usage and shrink costs in use cases such as these, especially satellite RAN resources, and enable on-demand services to be provided from the satellite RAN. The contrasting reasons are the large areas (2800 km diameter) of the satellite RAN's serving area, or field of view (FoV), and the occasional small number of users in some of those areas. Based on 3GPP standards, this is rather wasteful and too costly to implement. The present disclosure provides 100% wireless coverage in vast remote areas not yet covered by the TN, and only occasionally used, at an extra resource cost of less than 0.0001% of a normal TN deployment. The most important difference is that vast areas that are not covered or about to be covered can be covered or connected by the present disclosure, fundamentally solving the 0G problem on a truly global scale without much extra cost.

[0033] In this disclosure, the user equipment (UE) is referred to as a "smartphone." However, in one or more embodiments, the user equipment referred to as a "smartphone" may be any type of device that transmits and receives wireless communication signals, such as a smart watch, a fitness band, a tablet PC, an access point (e.g., hotspot), smart glasses, NB-IoT, etc.

[0034] A satellite cellular system (satellite mobile phone system), shown in Figure 1, consists of multiple large antennas on a satellite to generate a large number of narrow beams for user links and gateway beams with large operational bandwidth for routing user beam traffic and network access information to and from a gateway station or associated terrestrial network.

[0035] FIG. 1 shows a high power large phased array satellite system 10 that forms multiple beams 212 covering multiple small terrestrial cells 232 on a field of view (FOV) 230 of a given satellite 210. The system 10 includes a base station 100 that communicates with the satellite 210. The base station 100 may have a base transceiver, also called a baseband unit (BBU), such as a BTS in 2G and multiple eNodeBs 120 in 4G systems, and a processor / core 140 (such as a BSC switch core in 2G and an EvolvedPacketCore in 4G systems) that communicates with the Internet 110. The present disclosure has a small and lightweight sub-BBU system for a RACH detector on the satellite (see FIG. 2A, (P)RACH detector 120 (C) of satellite 210) that is introduced to further save feeder link bandwidth. The BBU 120 communicates signals to and from a gateway 150 which has an antenna, such as a directional antenna, that communicates with a satellite 210 via a gateway link signal 152. In one embodiment, the satellite 210 may be a single satellite unit. In another embodiment, the satellite 210 may be multiple satellite antenna elements such as those disclosed in U.S. Patent No. 9,973,266, the entire contents of which are incorporated herein by reference.

[0036] The satellite 210 receives the gateway antenna signal 152 and retransmits it as a signal to a number of user terminals located within the satellite's FOV 230, which includes one or more cells 232. The satellite signal includes a number of multi-beam user links consisting of a nominal (normal, scheduled, micro) beam (NB) 212 and a wide (macro) beam (WB) 214 provided by the satellite's phased array antenna.

[0037] Unmodified user devices connect to these beams 212, 214 to connect to local cell towers of the terrestrial system. Signals to / from the user devices are routed by the satellite system to / from the gateway 150 via high-throughput gateway feeder links (such as Ka-band links, Q / V-band links, or laser links). The total bandwidth of the gateway links is sufficient to accommodate the aggregated signals from all beams (cells), including traffic and network / access signals. In the gateway 150, the user signals are digitally and / or analog processed and interfaced with custom base transceivers, such as multiple BTSs, multiple eNodeBs, and multiple gNodeBs 120.

[0038] These customized BBUs 120 provide a standards-compliant interface to unmodified user equipment, allowing it to connect to the satellite communications system in the same way it would to a local tower, while compensating for the effects of the satellite communications system (such as delay and Doppler shift). The BBUs 120 are modified to tolerate the large delays due to signal propagation to and from the satellite 210. The delay and Doppler shift are compensated for at the center of each cell (beam), so the differential delay and Doppler over a size-limited cell is small and within the capabilities of a standard UE.

[0039] With reference to FIG. 2A, various functions and operations according to the present disclosure may be performed (implemented in) by a communication system 200A including, for example, a processing device. In one embodiment, the communication system has a ground station 150 including one or more BBUs (shown here as a first BBU 120A and a second BBU 120B) and a database for storing information. In some embodiments, the ground station 150 has a BBU pool (a shared facility of BBUs, BBUs used in a shared manner). The ground station may be located at the edge of a city. The processing device may be a BTS, eNodeB or gNodeB (BBU) and may include one or more of a wide variety of components or subsystems including, for example, a wired or wireless communication link and / or at least one storage device such as a memory or database. All or a portion of the systems, processes, and / or data utilized in the present disclosure may be stored in or retrieved from a storage device. The ground station communicates with multiple UEs 250 of multiple cells 232 via satellites 210. An exemplary path traveled by satellite 210, for example, a portion of low earth orbit (LEO), is shown by dashed line 254. The processing unit is capable of executing software that may be stored in the storage device. Unless otherwise indicated, the process is preferably performed automatically by the processor in substantially real time without delay.

[0040] A remote area (low call volume) access beam or signal 252 larger than the normal spot beam cell area (48 km diameter) may be processed by the on-board sub-BBU system for the RACH detector 120C only. The wide beam 252 transmits enough power for multiple UEs to acquire a low bandwidth cell (either a GSMARFCN (GSM ARFCN, Absolute Radio-Frequency Channel Number) of 200 kHz or the lowest LTE CBW allowed for the band used). If the call is one of these UEs 250, the carrier may broadcast system information, provide paging, and also detect the RACH (Random Access CHannel). This may be a GSM channel for example, and may occupy only 200 kHz.

[0041] When a UE becomes active in the wide beam 252 area, for example by making a data call, the PRACH detector of the first BBU 120C detects that the UE is active and generates a CFRA (Contention Free Random Access). The sub BBU 120C transmits (forwards) the CFRA to the second BBU 120B (BBU active beam). The second BBU may have multiple active cells predefined for this wide area (see Figures 3A-3C). Upon receiving a CFRA (e.g., RACH for GSM or PRACH (Physical Random Access CHannel)) from the PRACH detector of the first BBU 120A, the second BBU 120B continues the response by configuring a normal Rx beam 212 in the new active cell identified by the corresponding Rx beam detected by the (P)RACH, where the TA is within the expected range of the UE 250 as per the 3GPP definition (usually a prerequisite for best serving cell).

[0042] (P)RACH detector 120(C) may send an activation request to BBU 120B to handover to 120A and eliminate the service request of the newly active UE by providing the required active service using the same cell ID, or change to another cell (such as 2g to 4G) if necessary. In this example, the BBU active beam 212 provides the required service to a given (specified) beam / area for the cell in which the UE is active. Thus, the UE in that cell will communicate via the active beam 212, and the wide access beam 252 will continue to communicate with all cells 232 and perform its inactive wide cell duties for other access cells. When the UE 250 disconnects and the cell becomes inactive again, the active BBU 120B will stop serving and the access or inactive beam 252 will serve the area as an access cell. The cycle from inactive to active and back to inactive applies to the demand.

[0043] With reference to FIG. 2B, various functions and operations according to the present disclosure may be implemented in (performed by) a communication system 200B including, for example, a processing device. In one embodiment, the communication system includes a satellite 210 providing an inactive wide beam (e.g., GSM beam C19) 250. In this example, the beam 250 provides communication services (coverage) to a cluster of multiple cells 256 (e.g., C19). In some embodiments, each cell and cluster of cells may have its own TRx cell from at least one satellite. This allows a network control center (NCC) to balance system load and manage system resources. Additionally, load balancing of multiple feeder links and multiple eNBs, inactive / active cells, and cell bandwidth (CBW) can be applied on demand and changed as needed. Duplicating a cluster such as C7 may be similarly easy to use for feeder links when power is a / v (price fluctuating). In some embodiments, a power efficient approach is provided based on power, area, distance, and elevation angle. To effectively balance resources, different variations may be used, see Table 1: [Table 1]

[0044] In some embodiments, a method is provided to detect which cells are active cells in a wider inactive beam (IAB). Just turn on the Rx beam for each of the narrow beams in the inactive wide beam cluster while maintaining one wide Tx beam for the whole cluster. To be more efficient, some of the BBUs in 120A can be replicated in the satellite (on-board) and referenced to the (P)RACH detector 120(C), and the (P)RACH detection can be performed without using extra bandwidth on the feeder link. Although there is only 1T1R feeder link pair, it can handle 7-19 normal cell sizes in C7 and C19 configurations. This saves 7 or 19 times the feeder link and solar power resources compared to using 7 or 19 active beams (AB), and there is no problem with paging, TAC, setup and teardown of NWS1 connections (when there are no active UEs), and 1T1R can be preserved. Therefore, instead of making all IABs AB, you can just enable Rx Beams to streamline the process and improve the user experience.

[0045] Another example feature of the disclosed technology is the consideration of paging to the IAB and how to do it and participate in the RACH follow up. This feature makes a real difference in the actual service. The coverage (communication service) covers MT calls (mobile terminated, i.e. when someone calls a UE in a remote cell with IAB). Yet another feature of the disclosure is the signal processing equipment on the satellite for the (P)RACH detector 120(C) and added for Rx beam assistant to assist in RACH / PRACH detection.

[0046] With reference to Figures 3A-3C, three non-limiting examples of cell clusters at different frequencies are provided. The multiple cell clusters may be, for example, cell cluster 256 of Figure 2B. In some embodiments, the use of a hybrid system with a wider GSM BCCH (Broadcast Control Channel) ARFCN and an additional multi-RAT (2G+4G) pool of BBUs with various cell bandwidths (CBW) may be provided. In this exemplary hybrid system, the demand for thousands of cells served by one ground station (GS) via mobile services of several satellites can be dynamically met. In Figure 3A, an exemplary cluster of seven cells (e.g., C7) is shown at 10 MHz. In Figure 3B, examples of clusters of cells (e.g., C1, C7, C19) are shown. In Figure 3C, another example of a cell cluster (e.g., C3) each operating at a frequency of 5 MHz is shown.

[0047] The system uses GSM 200 kHz BW for inactive (non-active) cells and acquires RACH for multiple UEs. There are three different types of RACH to indicate the UE's intention so that the BTS at the gateway site can either invoke a CS voice call or use an RRC reconfiguration message to move the UE to an LTE cell when back-switched data services are required. At the same time, the location of the UE is known and active LTE beams are available for the UE's location area.

[0048] In some embodiments, an inactive cell has only DL signals, i.e., FCCH, SCH, and SIB in 2G, and PSS / SSS / CRS / MIB / SIB in 4G, and paging is required as MT call support in both 2G and 4G examples, but remains an inactive cell until a (P)RACH is detected. Furthermore, the RACH triggers a wide inactive cell to an active cell in a narrow spot beam. When the user's device performs a location area or tracking area update, the cell transitions to an active cell. Each cell, whether inactive or active, remains an inactive cell or becomes an inactive cell upon expiration of the cell inactivity timer as described herein. For an inactive wide cell, when a RACH is detected, two actions are taken, one of which is that the WB access cell transitions to a NBTRx (NB TRx) spot beam on the identified active cell / beam, which becomes the new active cell. For example, in the case of a RACH for a GSM voice call, the processing of the GSM call starts from the same inactive cell that the UE found. In the case of a data call, the 2G RRC reconfiguration message forwards it to the LTE cell that processes the LET CFRA PRACH. The previous access WB is given a different ARFCN and takes over the role of the inactive cell.

[0049] In one embodiment, the inactive wide beam may include a cluster of 7-19 inactive cells within a circular area of ​​160 km diameter or more, much larger than the Timing Advance (TA) range defined in the 3GPP specifications, up to 100 km for 4G and 120 km for 2G with extended TA. The solution is to employ multiple Rx beams from multiple spot beams, with on-board (P)RACH detectors. The actual communication to the UE is still arranged within the NB active cells, with no impact or violation to the RAN of the TA range defined for the unchanged UE.

[0050] In some embodiments, one 1.4 MHz CBW can be provided for each inactive cell if the band, feeder link BW, and on-board power allow. Alternatively, one 1.4 MHz CBW may be provided for each 7 and 19 inactive cell cluster if the band allows, but GSM access of the WB cells is a much better alternative if feeder link BW and on-board power are insufficient. As a further alternative, if the band does not allow 1.4 MHz, GSM is the only best way to access the WB cells.

[0051] For a new active UE, its mobility must also be considered. There are two ways to handle this. The best way is to track and always cover the UE with an electronically steerable beam. This can be done with TA and delay and Doppler corrections to the moving cell center. The other way is to change the serving BBU to an adjacent spot beam. Both are standard active beam configurations for satellite RAN operation and should be used in this case too.

[0052] The satellite system disclosed herein may operate with user equipment, including standard mobile phones, that are not modified for the NTN. Application of the present techniques can result in more efficient use of resources such as power and radio spectrum usage. Additionally, application of the disclosed techniques can result in power savings in the satellite RAN and TN.

[0053] Referring to flow chart 400A of FIG. 4A, an exemplary method for managing resources of a Satellite Access Network (SatRAN) is shown. The method may be implemented (performed) in one or more modules of a base station 100, a central processor beamforming unit (CPBF) of a satellite 210, an access cell baseband unit (BBU) subsystem 110, or a combination thereof. For ease of explanation, the following steps are described as the contents of FIG. 4B and FIG. 4C. However, these various operations may be performed by alternative components. Furthermore, these various operations may be performed in different orders. Furthermore, some operations may be performed simultaneously, some may not be required, or other operations may be added.

[0054] Flowchart 400 shows the operation (processing) of, for example, C7 (macro cluster cell (large cluster cell, macro cluster cell) with seven micro cells (small cells, micro cells), in which the micro cells are numbered 1-7 in FIG. 4B and FIG. 4C. Starting at step 404, as shown in FIG. 4B, the first BBU 120A transmits a wider macro inactive transmit (Tx) beam 214 to a wider macro access cell (having micro cells 1-7) in a remote location such as a part of the ocean, which then receives separately via a normal micro receive (Rx) beam 212 at step 402. The Central Processor Beam Forming (CPBF) unit of the satellite 210 processor processes not only the TRx beam but also different numbers of beams by forming beams for Tx and Rx to different cells and tracking them through the giant phased array 210 while the satellite 210 orbits above the cells.

[0055] Additionally or alternatively, the CPBF and BBUs 120 can provide multi-RAT (radio access technology), such as by switching between 2G, 4G, and 5G. Multi-RAT is part of the 3GPP standard and can be used as a mechanism to conserve power and spectrum, and as an option for resource management in the satellite RAN. To conserve bandwidth on the feeder link, a baseband subsystem is provided in the satellite's processor, which handles the (P)RACH detector 120 (C), which processes the TRx beams in step 406, cycles the system's broadcasting in step 408, and detects and processes potential RACH and paging in step 410 autonomously while maintaining a minimum link with the terrestrial gateway station's BBU farm via the feeder link. Once the RACH is detected by any Rx beam, the inactive wide macro Tx beam 214 (Figure 4B) may be changed or transitioned to be utilized as the active Tx micro beam 214A (Figure 4C), while, for example, the active Tx micro beam 214A (which communicates only with the active micro cell in which the active UE with a stronger signal is detected) has the same frequency and / or channel and / or phase as the inactive wide macro Tx beam 214 (which communicates with the entire macro cell cluster C7 with a weaker signal).

[0056] Delay and Doppler compensation may be provided for the cell center of the new active spot beam 214A. At the same time, the previous wide (wider, wider) inactive beam 214 may be replaced by another GSM inactive cell macro Tx beam 216 (FIG. 4C) by the BBU on another ARFCN in step 412, so that any additional RACHs can be handled in a wider range and feeder links can be immediately assigned by the BBU pool (jointly used BBUs) to serve users in the normal cell. The BBUs 120A and 120B cooperate to enable the new wide inactive beam 216 to replace the previous inactive beam 214 (FIG. 4B), as shown in FIG. 4C. Similar to the transition between IAB and AB, this is a transition between multiple RATs, serving the purpose in a much wider range and solving problems with a wider choice and granularity to better fit more situations. The described GSM to 4G RACH is a much better way to handle the satellite RAN RACH problem, avoiding preemptive CBRA without wasting resources and solving the 40 ms RTT. In some embodiments, timers can be used for decision making. Additionally or alternatively, the location of the user device may be used to assist in the decision to locate the AB.

[0057] Thus, once an active UE is detected, the first access wide Tx macro beam 214 (FIG. 4B) communicating with macro cell C7 transitions to a micro beam 214A, which communicates only with the active micro cell (micro cell 1 in FIG. 4C). The first macro cell downlink transmit (Tx) beam is generated to cover multiple micro cells in the macro field of view to communicate with the multiple micro cells in the macro field of view. Each of the multiple micro cells is associated with a separate and independent micro uplink receive (Rx) beam. The system then detects a UE access request from a UE located in at least one of the multiple micro cells in the macro field of view, and the access request is transmitted via a micro cell uplink Rx beam associated with at least one of the multiple micro cells.

[0058] Additionally, once an active UE is detected, a new inactive wide Tx macro beam 216 is formed that communicates with macro cell C7 on a different channel and / or frequency and / or phase than the active micro beam 214A. That is, in response to a UE access request, the first macro cell downlink Tx beam communicates only to the micro cell associated with that UE access request as an active micro downlink Tx beam, which serves the UE associated with that UE access request. Although the first wide Tx beam 214 is described as being replaced by the new wide Tx beam 216, the beams 214, 216 need not be the same beam, but may be different beams.

[0059] Finally, further in response to the UE access request, a second macrocell downlink Tx beam is generated that covers multiple microcells in the macro view and communicates with multiple microcells C7 in the macro view.

[0060] It should be noted that the micro receive Rx beams do not need to be changed after the UE access request is detected, rather, they may remain the same, although in some embodiments, different micro Rx beams may be utilized.

[0061] A network control center (NCC) may be provided to record events as they occur in order to perform data collection. According to one or more embodiments, multiple cells may report their running state (e.g., inactive / active) to the NCC. These reports may be provided periodically (e.g., every 5 minutes) for BHO decisions. These reports may also include the load capacity of each cell (e.g., 0% for inactive and 100% for full capacity). In some embodiments, the network manager may provide updated (latest) reports of the state of the network, current demand, expected demand, and when to transition a cell between inactive and active or vice versa. BHO opportunities would be at least the timing of changing AB to IAB if such a change is appropriate. BHO may occur, for example, every 4 to 5.5 minutes, which complements effective on-demand resource management as described by the disclosed technology. Additionally, network management decisions may include which RAT and BW to use. An inactivity timer may be assigned a value T1. Records may be kept and updated continuously.

[0062] In some embodiments, a module of the on-board BBU subsystem may determine if a cell is idle (e.g., inactive). If not, the cell is an active cell. If idle, upon termination of a call, an inactivity timer for the idle cell is started in the process of returning to an inactive call. Additionally, one or more modules may determine, with the gateway, if an active cell should revert to being part of the inactive cells. The process may then loop back to managing the IAB and AB like clockwork.

[0063] In some embodiments, the GSM 200 kHz BW is used to obtain a RACH from a user device in an inactive cell. There are three different types of RACH to indicate the user equipment's intent, so the BTS at the gateway site may invoke a CS call or use an RRC reconfiguration message to move the user equipment to an LTE cell when back-switched data services are required. At the same time, the location of the user device is known by the individual Rx 212 and an active LTE beam may be available for the device's location area.

[0064] In some embodiments, the inactive cell has PSS / SSS / RS / MIB / SIB as DL signals and paging as support for MT calls and remains an inactive cell until RACH is detected. RACH is the trigger from a wide inactive cell to an active cell in narrow spot beam. If there is a user device performing a location area or tracking area update, that cell becomes an active cell. Each cell, whether inactive or active, remains an inactive cell or becomes an inactive cell when the cell inactivity timer expires. As described herein, the inactive wide cell opens multiple Rx spot beams for its multiple subnormal cells on the detected RACH and identifies the best serving beam, which becomes the new active cell.

[0065] 5 illustrates a simplified functional block diagram of an exemplary multifunction device 500 in one embodiment. Multifunction device 500 is a representative component for, for example, devices of base station 100, operator IP services of Internet 110, and devices of satellite 210 of FIG. 1. Multifunction electronic device 500 may include a processor 505, a display 510, a user interface 515, graphics hardware 520, communication circuitry 545, memory 560, storage device 565, and a communication bus 570. Multifunction electronic device 500 may be, for example, a personal electronic device such as a personal digital assistant (PDA), a personal music player, a mobile phone or smartphone, or a tablet computer.

[0066] The synchronization unit 525 is key to the system clockwork, allowing the processor 505 to control the packing of the feeder links and perform dynamic cell handling including IAB and AB changes as well as BHO to other satellites in orbit using the feeder link M&C (maintenance and control) channels. As the feeder links 152 are wideband multi-gigahertz links providing the lifeline for each satellite, it is important to manage multiple IABs and ABs. This saves more than 50% of the resource usage and is therefore essential to the operation of the entire satellite RAN as a whole.

[0067] Processor 505 may execute instructions necessary to perform or control the operation (processing) of the many functions performed by device 500. Processor 505 may, for example, drive display 510 and receive user input from user interface 515. User interface 515 may allow a user to interact with device 500. For example, user interface 515 may be in various forms, such as buttons, keypads, dials, click wheels, keyboards, display screens, and / or touch screens. Processor 505 may also be a system-on-chip, such as found in mobile devices, for example, and may include a dedicated graphics processing unit (GPU). Processor 505 may be based on a reduced instruction set computer (RISC) architecture or a complex instruction set computer (CISC) architecture, or any other suitable architecture, and may include one or more processing cores. Graphics hardware 520 may be dedicated computer hardware for processing graphics and / or assisting processor 505 in processing graphics information. In one embodiment, graphics hardware 520 may include a programmable GPU.

[0068] Data can be stored in memory 560 and / or storage 565. Memory 560 may include one or more different types of media used by processor 505 and graphics hardware 520 to perform functions as a device. For example, memory 560 may include memory cache, read-only memory (ROM), and / or random access memory (RAM). Storage 565 can store media (e.g., audio, image and video files), computer program instructions or software, preference information, device profile information, and any other suitable data. Storage 565 may include one or more non-transitory computer-readable storage media, including, for example, magnetic disks (fixed, floppy, and removable) and tapes, optical media such as CD-ROMs and digital video disks (DVDs) (DVDs), and semiconductor memory devices such as electrically programmable read-only memories (EPROMs) and electrically erasable programmable read-only memories (EEPROMs). The memory 560 and storage 565 may be used to practically hold computer program instructions or code, organized into one or more modules and written in any desired computer programming language, that, when executed by the processor 505, for example, may perform one or more of the methods described herein.

[0069] It will be apparent to those skilled in the art having the benefit of the teachings set forth in the foregoing description and the associated drawings that modifications, combinations, subcombinations, and variations may be made without departing from the spirit or scope of the present disclosure. Similarly, the various embodiments described may be used individually or in combination with other embodiments. Those skilled in the art will appreciate that various combinations of the embodiments not specifically described or illustrated herein will still fall within the scope of the present disclosure. In this regard, it should be understood that the present disclosure is not limited to the specific embodiments set forth, and that the embodiments of the present disclosure are intended to be illustrative, rather than limiting.

[0070] Unless otherwise specified, one or more particular features and / or elements described in connection with one or more embodiments may be found in one embodiment, more than one embodiment, all embodiments, or none of the embodiments. Although one or more features and / or elements may be described herein in the context of only a single embodiment, or in the alternative, in the context of multiple embodiments, or even alternatively, in the context of all embodiments, the features and / or elements may alternatively be provided separately, in any suitable combination, or not at all.

Claims

1. A satellite communication system At least one base station having a scheduling capability configured to communicate with a standard-compliant user equipment (UE) via a satellite with one macro field of view, at least one of the at least one base station comprising a processor: generating a first macrocell downlink transmit (Tx) beam covering a plurality of microcells within the macro field of view, each microcell being associated with a respective independent microcell uplink receive (Rx) beam; Detecting a UE access request from a UE located in at least one of the plurality of micro cells within the macro field of view, the UE access request being sent via the micro cell uplink Rx beam associated with the at least one of the plurality of micro cells; in response to the UE access request, transitioning the first macro cell downlink Tx beam to an active micro downlink Tx beam and communicating only with a micro cell associated with the UE access request, the active micro downlink Tx beam providing service to the UE associated with the UE access request; and A satellite communications system having a memory for storing instructions to execute, in response to the UE access request, generating a second macrocell downlink Tx beam to replace the first macrocell downlink Tx beam and cover the multiple microcells within the macro field of view.

2. In claim 1, A satellite communication system, wherein the first macrocell downlink Tx beam is configured to transmit system and paging information.

3. In claim 1, A satellite communications system, wherein the first macrocell downlink Tx beam is configured to cover a wider band than the active micro downlink Tx beam.

4. In claim 1, The at least one base station includes a plurality of base stations, each of the plurality of base stations being ,A satellite communication system having round-trip-time (RTT)-aware scheduling capability.

5. In claim 4, A satellite communication system, wherein the RTT is 40 milliseconds.

6. In claim 4, A satellite communications system, wherein said aware scheduling function is performed by a Delay and Doppler Compensation (DD&C) unit.

7. In claim 1, A satellite communications system, wherein the first macrocell downlink Tx beam has a first frequency, the active micro downlink Tx beam has the first frequency, and further, the second macrocell downlink Tx beam has a second frequency different from the first frequency.

8. In claim 1, A satellite communication system, wherein the active micro downlink Tx beam does not communicate with the plurality of micro cells in which the UE access request was not detected.

9. In claim 1, A satellite communications system, wherein the system is configured to operate in a Global System for Mobile Communications (GSM) mode.

10. 1. A satellite having a baseband unit (BBU), the BBU comprising a scheduling function configured to communicate with a standard-compliant user equipment (UE) via the satellite, the BBU further comprising a processor configured to: generating a first macrocell downlink transmit (Tx) beam covering a plurality of microcells within a macro field of view, each microcell being associated with a respective independent microcell uplink receive (Rx) beam; Detecting a UE access request from a UE located in at least one of the plurality of micro cells within the macro field of view, the UE access request being sent via the micro cell uplink Rx beam associated with the at least one of the plurality of micro cells; in response to the UE access request, transitioning the first macro cell downlink Tx beam to an active micro downlink Tx beam and communicating only with a micro cell associated with the UE access request, the active micro downlink Tx beam serving the UE associated with the UE access request; and a satellite comprising a memory for storing instructions to execute, in response to the UE access request, generating a second macrocell downlink Tx beam to replace the first macrocell downlink Tx beam and cover the multiple microcells within the macro field of view.

11. In claim 10, A satellite, wherein the BBU includes a random access channel (RACH) detector.

12. In claim 11, The satellite, wherein the RACH detector is a Global System for Mobile Communications (GSM) RACH detector.

13. 1. A method for satellite communications comprising using at least one computing device, the using the at least one computing device comprising: generating a first macrocell downlink transmit (Tx) beam covering a plurality of microcells within a macro field of view, each microcell being associated with a respective independent microcell uplink receive (Rx) beam; Detecting a user equipment (UE) access request from a UE located in at least one of the plurality of microcells within the macro field of view, the UE access request being sent via the microcell uplink Rx beam associated with the at least one of the plurality of microcells; in response to the UE access request, transitioning the first macro cell downlink Tx beam to an active micro downlink Tx beam and communicating only with a micro cell associated with the UE access request, the active micro downlink Tx beam serving the UE associated with the UE access request; and generating, in response to the UE access request, a second macrocell downlink Tx beam to replace the first macrocell downlink Tx beam and cover the multiple microcells within the macro field of view.

14. In claim 13, The method of claim 1, wherein the first macrocell downlink Tx beam transmits system and paging information.

15. In claim 13, A method according to claim 1, wherein the first macrocell downlink Tx beam covers a wider band than the active micro downlink Tx beam.

16. In claim 13, A method according to claim 1, wherein the first macrocell downlink Tx beam has a first frequency, the active micro downlink Tx beam has the first frequency, and the second macrocell downlink Tx beam has a second frequency.

17. In claim 13, The method, wherein the active micro downlink Tx beam does not communicate with the plurality of micro cells in which the UE access request was not detected.

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