Improving return link capacity by using duplicate return link channels.

Abstract

Described herein are systems and methods for improving or optimizing return link capacity by employing overlapping return link channels within a return channel group (RCG) for a communication system shared by multiple user terminals. The disclosed techniques allow for simultaneous use of different return link channel configurations while reducing or eliminating the need for additional overhead messages associated with changing the configuration of the RCG. The disclosed techniques allow for more efficient use of return link capacity by responding in real time to changing conditions and demands.

Description

Technical Field

[0001] This disclosure generally relates to the allocation of transmission resources in a communication system.

Background Art

[0002] In network communication, data is transmitted and received between nodes such as a content server and a user terminal. To transmit user data via a network, a scheduler can be used to allocate network resources to devices and create a transmission schedule for the devices. Then, based on the schedule, each device can transmit data using the allocated resources. Based on the schedule, a user terminal can transmit data to a gateway that is part of the communication system and forward it to the final destination.

Summary of the Invention

[0003] In a first embodiment, the Disclosure provides a method for communicating in a communication system. The method includes receiving requests for return link bandwidth from a first user terminal and from a second user terminal. The method also includes assigning a first return link channel to the first user terminal, at least in part on the transmission characteristics of the first user terminal, the first return link channel being selected from a plurality of return link channels grouped into a return channel group, and the first return link channel including a first frequency band. The method also includes assigning a first transmit permission period to the first user terminal. The method also includes assigning a second return link channel to the second user terminal, at least in part on the transmission characteristics of the second user terminal, the second return link channel being selected from a plurality of return link channels in a return channel group, and the second return link channel including a second frequency band. The method also includes assigning a second transmit permission period to the second user terminal. The method also includes communicating a first return link channel, a first transmit permission period, a second return link channel, and a second transmit permission period to the corresponding user terminal. Each of the multiple return link channels in the return channel group has different transmission characteristics, with at least one return link channel having a frequency band that at least partially overlaps with the frequency band of another return link channel.

[0004] In some embodiments of the first aspect, the first user terminal has a different transmission rate than the second user terminal.

[0005] In some embodiments of the first aspect, the method further includes determining whether a first frequency band overlaps at least partially with a second frequency band, and whether a first transmit permission period overlaps at least partially with a second transmit permission period. In a further embodiment, the method includes assigning a third return link channel to a first user terminal in response to the determination that the first frequency band overlaps at least partially with a second frequency band and that the first transmit permission period overlaps at least partially with a second transmit permission period, wherein the third return link channel has a third frequency band that does not overlap with the second frequency band. In a further embodiment, the method includes assigning a third transmit permission period to a first user terminal in response to the determination that the first frequency band overlaps at least partially with a second frequency band and that the first transmit permission period overlaps at least partially with a second transmit permission period, wherein the third transmit permission period does not overlap with the second transmit permission period. In a further embodiment, the communication of the assigned return link channel and transmit permission period to the first and second user terminals is performed in response to a determination that the first frequency band does not overlap with the second frequency band, or that the first transmit permission period does not overlap with the second transmit permission period.

[0006] In some embodiments of the first embodiment, the return channel group is hardcoded to the first user terminal and the second user terminal. In some embodiments of the first embodiment, all possible return link channels of the communication system are included in the return channel group. In some embodiments of the first embodiment, each return link channel in the return channel group has a common center frequency. In some embodiments of the first embodiment, each return link channel in the return channel group has a common lower end frequency.

[0007] In some embodiments of the first aspect, the method further includes periodically sending return channel group (RCG) descriptor messages to a first user terminal and a second user terminal, the RCG descriptor messages including updates to the return channel group. In further embodiments, the RCG descriptor messages include adding a return link channel to the return channel group, adjusting the center frequency of a return link channel within the return channel group, or adjusting the bandwidth of a return link channel within the return channel group.

[0008] In some embodiments of the first aspect, the first return link channel has a bandwidth greater than or equal to the transmission rate of the first user terminal, and the second return link channel has a bandwidth greater than or equal to the transmission rate of the second user terminal. In some embodiments of the first aspect, the transmission characteristics of the first user terminal are degraded due to the channel state of the communication system, and the first return link channel is assigned to the first user terminal based at least in part on the degraded transmission characteristics.

[0009] In a second embodiment, the Disclosure provides a communication system that provides communication over a network. The system includes a first user terminal having a first maximum bandwidth, the first user terminal being configured to store a group of return channels, which include a plurality of return link channels. The system also includes a second user terminal having a second maximum bandwidth, the second user terminal being configured to store a group of return channels. The system also includes a gateway configured to communicate with the first and second user terminals over the network. The gateway includes a scheduler configured to store return channel groups, assign a first return link channel from the return channel group to a first user terminal (the first return link channel includes a first frequency band) based at least partially on a first maximum bandwidth, assign a first transmit permission period to the first user terminal, assign a second return link channel from the return channel group to a second user terminal (the second return link channel includes a second frequency band) based at least partially on a second maximum bandwidth, assign a second transmit permission period to the second user terminal, and communicate the first return link channel, the first transmit permission period, the second return link channel, and the second transmit permission period to the corresponding user terminal. Each of the multiple return link channels in the return channel group has different transmission characteristics, with at least one return link channel having a frequency band that at least partially overlaps with the frequency band of another return link channel.

[0010] In some embodiments of the second embodiment, the network comprises a satellite network having at least one low Earth orbit satellite. In some embodiments of the second embodiment, the network comprises a satellite network having at least one medium Earth orbit satellite. In some embodiments of the second embodiment, the network comprises a satellite network having at least one geostationary Earth orbit satellite. In some embodiments of the second embodiment, the network comprises a ground network. In some embodiments of the second embodiment, the network comprises a cellular network.

[0011] In some embodiments of the second aspect, the first maximum bandwidth is different from the second maximum bandwidth. In some embodiments of the second aspect, the duty cycle of the first user terminal is different from the duty cycle of the second user terminal.

[0012] In some embodiments of the second embodiment, the first return link channel is assigned based at least in part on channel conditions that reduce the duty cycle of the first user terminal. In some embodiments of the second embodiment, the first return link channel is assigned based at least in part on channel conditions that reduce the first maximum bandwidth.

[0013] In a third aspect, the Disclosure provides a scheduler in a communication system. The scheduler includes a network interface configured to communicate with a first user terminal and a second user terminal via the communication system. The scheduler also includes a datastore configured to store computer executable instructions that generate a return link schedule, which allocates return link bandwidth to a user terminal in response to a return link bandwidth request from the user terminal, and to store a return channel group, which includes a plurality of return link channels. The scheduler also includes a processor configured to execute computer executable instructions to allocate a first return link channel, which includes a first frequency band, to the first user terminal from the return channel group; to allocate a first transmit permission period to the first user terminal; to allocate a second return link channel, which includes a second frequency band, to the second user terminal from the return channel group; to allocate a second transmit permission period to the second user terminal; and to communicate the first return link channel, the first transmit permission period, the second return link channel, and the second transmit permission period to the corresponding user terminal. Each of the multiple return link channels within a return channel group has different transmission characteristics, and the frequency bandwidth of at least one return link channel overlaps at least partially with the frequency bandwidth of another return link channel.

[0014] In some embodiments of the third aspect, the processor is further configured to determine whether a first frequency band overlaps at least partially with a second frequency band, and whether a first transmit permission period overlaps at least partially with a second transmit permission period. In further embodiments, in response to the determination that the first frequency band overlaps at least partially with a second frequency band and that the first transmit permission period overlaps at least partially with a second transmit permission period, the processor is further configured to assign a third return link channel to a first user terminal, the third return link channel having a third frequency band that does not overlap with the second frequency band. In further embodiments, in response to the determination that the first frequency band overlaps at least partially with a second frequency band and that the first transmit permission period overlaps at least partially with a second transmit permission period, the processor is further configured to assign a third transmit permission period to a first user terminal, the third transmit permission period does not overlap with the second transmit permission period. In a further embodiment, the processor is configured to communicate the allocated return link channel and transmit permission period to the first and second user terminals in response to a determination that the first frequency band does not overlap with the second frequency band, or that the first transmit permission period does not overlap with the second transmit permission period.

[0015] In some embodiments of the third aspect, all possible return link channels of the communication system are included in the return channel group.

[0016] In some embodiments of the third aspect, the processor is further configured to periodically send RCG descriptor messages to a first user terminal and a second user terminal, the RCG descriptor messages including updates to the return channel group. In further embodiments, the RCG descriptor messages add return link channels to the return channel group, adjust the center frequency of the return link channels in the return channel group, or adjust the bandwidth of the return link channels in the return channel group.

[0017] For the purpose of summarizing this disclosure, certain aspects, advantages, and novel features are described herein. It should be understood that not all such advantages are necessarily achieved according to a particular embodiment. Accordingly, the disclosed embodiments may be performed in a manner that achieves or optimizes one advantage or group of advantages taught herein, and do not necessarily have to achieve other advantages that may be taught or suggested herein.

[0018] The accompanying drawings depict various embodiments for illustrative purposes and should not be construed as limiting the scope of this disclosure. Furthermore, various features of the different embodiments disclosed can be combined to form additional embodiments that are part of this disclosure. [Brief explanation of the drawing]

[0019] [Figure 1A] Figure 1A shows an exemplary communication system that uses a satellite network and a scheduler to provide and manage communication between multiple user terminals and multiple gateway routing devices, and to provide access to a network (such as the Internet). [Figure 1B] Figure 1B shows another exemplary communications system that includes an access network and scheduler, providing and managing communication between multiple user terminals and multiple gateway routing devices, and providing access to the Internet (or other appropriate network). [Figure 2A] Figure 2A shows that each user terminal requests permission for resources on the satellite network from the scheduler via the gateway routing device. [Figure 2B] Figure 2B illustrates how the scheduler allocates resource blocks (time-frequency resources) in one or more time slots to respond to resource requests from user terminals. [Figure 2C] Figure 2C illustrates how the user terminal sends data from the buffer according to the time-frequency resources allocated by the scheduler. [Figure 3A] FIG. 3A shows an example of a plurality of return channel groups (RCGs) each without overlapping return link channels, the plurality of RCGs being configured for use in a particular communication system. [Figure 3B] FIG. 3B shows an example of RCG channelization that provides overlapping return link channels and has improved functionality compared to the RCG channelization set of FIG. 3A. [Figure 4A] FIG. 4A shows an example of an RCG with one return link channel having a frequency band overlapping with two other return link channels. [Figure 4B] FIG. 4B shows an exemplary resource grant map for assigning different user terminals to different return link channels, the return link channels corresponding to the return link channels within the RCG of FIG. 4A. [Figure 4C] FIG. 4C shows another exemplary resource grant map. [Figure 5A] FIG. 5A shows an in-slot assignment within a resource grant map. [Figure 5B] FIG. 5B shows an inter-slot assignment within a resource grant map. [Figure 6] FIG. 6 shows a flowchart of an exemplary method of communicating on a communication system that supports return channel groups with overlapping channelization. [Figure 7] FIG. 7 shows a block diagram of an exemplary scheduler configured to assign resource grants to a plurality of user terminals using an RCG with overlapping channelization. DETAILED DESCRIPTION

[0020] If headings are provided herein, they are for convenience only and do not necessarily affect the scope or meaning of the claimed embodiments.

[0021] SUMMARY A communication system can communicate with multiple terminals simultaneously over forward and return links. The forward link refers to the communication link from the base station to the terminal, and the return link refers to the communication link from the terminal to the base station. Multiple terminals can simultaneously transmit data over the return link and / or receive data over the forward link. The number of terminals that can communicate with the communication system at any given time may be limited by the number of physical channels available for data transmission, which are limited by the available system resources.

[0022] Various return link channels can be defined to manage transmissions from user terminals on a communication system. A return link channel can be defined by appropriate transmission characteristics such as characteristic frequency (e.g., center frequency, lower frequency, upper frequency, frequency offset, etc.) and bandwidth (e.g., transmission rate). A return link channel can also be defined to correspond to a specific transmission rate (e.g., symbol rate or chip rate). Thus, user terminals can be allocated transmission resources by requesting resources and being allocated a return link channel to use for return link transmissions during the transmission permission period.

[0023] In some embodiments, multiple return link channels can be grouped into a return channel group (RCG). An RCG may include multiple return link channels to provide return link channels for various transmission rates. In an RCG shared by multiple user terminals, return link channels may be defined as sequential and non-overlapping to reduce or minimize interference and increase or maximize capacity. Such a defined RCG can minimize interference by having at least partially non-overlapping frequency bands of return link channels and maximize capacity by having at least partially sequential frequency bands (e.g., the frequency bands of return link channels are adjacent to each other).

[0024] User terminals are allocated transmission resources on the return link using the return link channel from the RCG. The RCG may communicate to user terminals using messages (e.g., RCG descriptor messages) that propagate a description of the set of return link channels for the RCG throughout the communication system. The messages used to communicate the RCG can be achieved using any appropriate broadcast message that the communication system can use to send system information related to return link allocation to multiple user terminals.

[0025] When it is desirable to use an RCG with a different lineup of non-overlapping return link channels (for example, to accommodate the arrival of high data-rate user terminals or due to rain attenuation events), the change in channel lineup must propagate throughout the entire communication system, which can take an undesirably long time (e.g., several minutes). This delay is due to the process used to update the RCG, in which network components (e.g., schedulers) determine that it is advantageous to change the RCG based on user traffic requests or changes in channel conditions. This process propagates the RCG to user terminals using over-the-air (OTA) messages. Other components in the network (e.g., physical layer processing modules) may also require the updated RCG information to retune their components with the new channeling profile. This process may also involve user terminals adjusting their transmit chains to adapt to the new RCG. For example, user terminals may need to refine their physical layer control loops to optimize transmit parameters on the newly defined RCG. These steps of the process may require one or more round trips on the over-the-air link. This process can take undesirably long, sometimes exceeding several minutes for geosynchronous satellite links. This makes it difficult to respond quickly to changes in the communication network landscape that could affect the effectiveness or usefulness of the current RCG.

[0026] For example, situations may arise where channel conditions deteriorate (e.g., rainfall can negatively impact the transmission capacity of a satellite communication system). In such situations, it may be desirable to use a different RCG that includes more return link channels for transmission rates lower than those defined in the current RCG. This can be done to accommodate user terminals with reduced transmission rates under such circumstances. Otherwise, the deterioration of channel conditions could lead to bandwidth being allocated to user terminals that cannot utilize all of their allocated bandwidth, reducing the efficiency of the communication system. Another example is when high-capacity user terminals sporadically request higher throughput return link traffic. In such situations, it may be desirable to use a different RCG that includes available return link channels for higher transmission rates that are not defined in the current RCG. Otherwise, unused transmission capacity would exist in the communication system.

[0027] In situations like these, as described herein, it can take undesirably long to propagate different RCGs to user terminals and other components of the communication system. Therefore, this specification describes systems and methods for improving or optimizing return link capacity by employing overlapping return link channels within the RCG of a communication system shared by multiple user terminals. The disclosed technology enables the simultaneous use of different return link channel configurations while reducing or eliminating the need for additional overhead messaging associated with RCG changes. The disclosed technology enables more efficient use of return link capacity by responding in real time to changing conditions or requests.

[0028] The disclosed systems and methods specify multiple return link channels within a communication system and define an RCG to include each of these channels, where two or more of the channels have overlapping frequencies. In some embodiments, the RCG includes all possible return link channels in the communication system. In various embodiments, the return link channels are defined in the RCG using a unique channel identifier and frequency offset. In some embodiments, this RCG may be hardcoded into code in both the user terminal and the scheduler, or in other components such as base stations and ground stations. In certain embodiments, a periodic message is sent containing a list of all channels (including overlapping channels) in the RCG. In such embodiments, the user terminal reads the message to understand the return link channeling defined by the communication system. This can be done to retain the communication system's flexibility in changing channeling, which may be beneficial as the network evolves and new channels are introduced.

[0029] Because the disclosed RCG has overlapping channels, it is not possible to use all the channels defined in the RCG simultaneously. Therefore, the scheduler or other components in the communication system are configured to ensure that user terminals are scheduled in a non-overlapping manner. Non-overlapping time-frequency allocation avoids same-channel interference in certain communication systems, such as those employing multi-frequency time-division multiplexing (MF-TDMA). For example, if a user terminal is scheduled to transmit on a first channel during a first period, the scheduler is configured not to allow other user terminals to transmit on channels with frequency bands that overlap with the frequency band of the first channel during periods that overlap with the first period.

[0030] Advantageously, the disclosed technology can eliminate the need for channel reconfiguration algorithms or messaging, at least in part, because the disclosed RCG includes many or all possible channel configurations available in the communication system. Advantageously, the disclosed technology also allows terminals with different capabilities to coexist in the communication system. For example, a terminal capable of transmitting at 160 Mcps (megachips / second) can coexist with a terminal capable of transmitting at only 10 Mcps with minimal wasted bandwidth. Furthermore, the disclosed technology advantageously allows for different combinations of communication capabilities to exist and be active simultaneously in different aspects of the communication system. For example, it is possible for the first beam of a satellite to employ channel configurations that enable transmission at 160 Mcps, while another beam of the satellite employs channel configurations that do not include transmission at 160 Mcps.

[0031] Examples of communication systems Figure 1A shows a diagram of an exemplary communication system 100a that uses a satellite network 140a to connect multiple user terminals 110a, 110b, 110c and multiple gateway routing devices 150a, 150b in a communicative manner, providing access to a network (such as the Internet 160). The communication system 100a includes a scheduler 170 configured to allocate resource allocations to the user terminals 110a, 110b, 110c. The communication system 100a includes multiple gateway satellite transceivers 130a, 130b and multiple customer satellite transceivers 120a, 120b, 120c configured to send and receive signals over satellite 105.

[0032] The communication system 100a may utilize various network architectures, including space segments and ground segments. The satellite network 140a incorporates these components to provide communication between multiple user terminals 110a, 110b, 110c and gateway routing devices 150a, 150b. For example, the space segment may include one or more satellites, and the ground segment may include one or more satellite user terminals, gateway terminals, network operations centers (NOCs), satellite and gateway terminal command centers, and / or similar. Some of these components are not shown for clarity. The satellite network 140a may include one or more geosynchronous orbit (GEO) satellites, one or more medium orbit (MEO) satellites, and / or one or more low orbit (LEO) satellites. It should be understood that satellite 105 can represent one or more satellites, and one or more satellites may include GEO satellites, MEO satellites, LEO satellites, or any combination thereof.

[0033] User terminals 110a, 110b, and 110c may include routers or other user equipment and may be configured to send and receive data routed via the communication system 100a. User terminals 110a, 110b, and 110c may include or be communicably coupled to any type of consumer premises equipment (e.g., telephones, modems, routers, computers, set-top boxes, etc.). User terminals 110a, 110b, and 110c are configured to send and receive data using the satellite network 140a via their respective customer satellite transceivers 120a, 120b, and 120c. Customer satellite transceivers 120a, 120b, and 120c may include a phased array antenna, two antennas (e.g., one for transmitting and one for receiving), or multiple antennas, each accessing a different satellite or communication path.

[0034] The satellite network 140a provides forward links for transmitting information from gateway routing devices 150a, 150b to user terminals 110a, 110b, and 110c, and return links for transmitting information from user terminals 110a, 110b, and 110c to gateway routing devices 150a, 150b. The forward and return links are sometimes referred to as over-the-air (OTA) signals or communication paths. The forward links include a transmission path from gateway routing devices 150a, 150b through their respective gateway satellite transceivers 130a, 130b, via satellite uplink channels through satellite 105, via satellite downlink channels to customer satellite transceivers 120a, 120b, and 120c, and to user terminals 110a, 110b, and 110c. The return link includes a transmission path from user terminals 110a, 110b, and 110c, through their respective customer satellite transceivers 120a, 120b, and 120c, through satellite 105 via the satellite uplink channel, to gateway satellite transceivers 130a and 130b via the satellite downlink channel, and to gateway routing devices 150a and 150b. It should be understood that each communication path may utilize multiple satellites and transceivers.

[0035] The scheduler 170 is configured to manage the allocation of communication resources to user terminals 110a, 110b, and 110c. The scheduler 170 may be part of the gateway routing devices 150a and 150b, or it may be a separate component of the communication system 100a. Furthermore, communication resources may be managed by multiple components of the communication system 100a. In some embodiments, some or all of the gateway routing devices 150a, 150b and / or the scheduler 170 may be located as virtual devices residing in a public or private computing cloud and / or as part of a distributed computing environment. The scheduler 170 may be configured to manage resources for multiple gateway routing devices 150a, 150b, as well as for user terminals 110a, 110b, and 110c.

[0036] In some embodiments, one or more of the user terminals 110a, 110b, and 110c may be configured to communicate with different communication systems (e.g., satellite systems such as GEO satellites, MEO satellites, and / or LEO satellites, cellular systems such as LTE (Long Term Evolution) technology, and / or terrestrial systems such as Digital Subscriber Line (DSL)) using different customer satellite transceivers 120a, 120b, and 120c. Thus, for user terminals 110a, 110b, and 110c, multiple communication paths can exist between the user terminals and the Internet 160. In some embodiments, the communication system 100a (e.g., the scheduler 170) is configured to select a desirable, efficient, or optimal communication path for user terminals 110a, 110b, and 110c from among the multiple communication paths available to the user terminals.

[0037] As described herein, return link channels are grouped into return channel groups (RCGs). An RCG disclosed herein includes a plurality of return link channels, each having a frequency band in which at least one return link channel overlaps with another. In some embodiments, an RCG disclosed herein specifies many or all possible return link channels available to a communication system 100a. A communication system such as communication system 100a has a finite number of channels that can be used in the system, and the number of channels depends on various system constraints such as time and frequency quantization and the number theory of the system. In a particular implementation, the number of return link channels may be limited by the available frequency band. As used herein, all possible return link channels in a communication system can be defined as the total number of return link channels available in the communication system, which depends on various system parameters. For example, a communication system may use an RCG defined in a license spectrum uniquely determined by the frequency span (e.g., parameterized by lower frequency, upper frequency, and channel bandwidth). Given a frequency bandwidth, a simple channelization method for return link channels within an RCG may involve several parameters, such as a minimum channel bandwidth and a scale factor. In such a channelization method, the bandwidth of each return link channel is given by BW_min*SF^nMcps, where BW_min is the minimum channel bandwidth, SF is the scale factor, and n is a non-zero positive integer. Thus, it is possible to determine all possible sets of return link channels for a given method.

[0038] As a specific example, a communication system could use a 500 MHz channel in the Ka-band spanning the 21.0 GHz to 21.5 GHz frequency range, with a minimum channel bandwidth (BW_min) of 5 Mcps and a scale factor (SF) of 2. The possible return link channel bandwidth in such a scheme is 5 * 2^n Mcps. Since the maximum RCG bandwidth is 500 MHz, the maximum return link channel bandwidth is 320 Mcps. In other words, with this channeling scheme, the return channel bandwidth can be 5, 10, 20, 40, 80, 160, or 320 Mcps. Considering the bandwidth of the frequency range, the set of all possible return link channels for this scheme includes 100 possible 5Mcps channels, 50 possible 10Mcps channels, 25 possible 20Mcps channels, 12 possible 40Mcps channels, 6 possible 80Mcps channels, 3 possible 160Mcps channels, and 1 possible 320Mcps channel. In some embodiments, overlapping channels of different bandwidths may have a common lower end frequency. In various embodiments, overlapping channels may have a common center frequency.

[0039] In some embodiments, the RCG is hardcoded into the scheduler 170 and user terminals 110a, 110b, and 110c. In some embodiments, the RCG can be modified by the scheduler 170, and changes to the RCG can be communicated to user terminals 110a, 110b, and 110c and other components of the communication system 100a through RCG descriptor messages.

[0040] The scheduler 170 is configured to use the RCG to allocate transmission resources on the return link to user terminals 110a, 110b, and 110c. For example, for each user terminal 110a, 110b, and 110c that requests bandwidth on the return link, the scheduler 170 allocates a transmit permission period and a return link channel from the RCG. The return link channel has an associated frequency and bandwidth (e.g., corresponding to a frequency band). The scheduler 170 may be configured to allocate a return link channel to a particular user terminal based at least in part on the transmission characteristics of the corresponding user terminal. For example, a return link channel may be configured to accommodate a specific transmission rate (e.g., symbol rate or chip rate), and the scheduler 170 may be configured to allocate a return link channel to a user terminal that can achieve the specific transmission rate supported by the return link channel. For example, the scheduler 170 may be configured to allocate a return link channel with bandwidth to accommodate a transmission rate of 80 Mcps to a user terminal capable of transmitting at 80 Mcps. The capabilities of a user terminal are influenced by its hardware components, such as filters and amplifiers, which affect transmission characteristics such as power and bandwidth. Furthermore, the capabilities of a user terminal are related to user terminal parameters such as maximum power and terminal antenna performance / off-axis. Therefore, the scheduler 170 is configured to allocate return link channels based at least partially on the capabilities of each user terminal, which are influenced by components affecting transmission characteristics.

[0041] In some embodiments, the scheduler 170 may assign different RCGs to different aspects of the communication system 100a, such as a satellite network 140a. For example, the scheduler 170 may assign a first RCG having a first channeling scheme to a first communication link (e.g., a beam) of the communication system 100a, and a second RCG having a second channeling scheme different from the first to a second communication link. Different RCGs with different channeling schemes allow different devices to communicate simultaneously over their respective communication links.

[0042] For example, the first beam of satellite network 140a may be assigned a first RCG that serves one or more user terminals 110 (fixed and / or mobile) capable of transmitting at 80 Mcps and 160 Mcps, and employs a first channeling scheme that enables device communication at both 80 Mcps and 160 Mcps. However, the second beam of satellite network 140a may be assigned a second RCG that serves one or more user terminals 110 (fixed and / or mobile) capable of transmitting at a maximum of 80 Mcps, and employs a second channeling scheme that does not enable device transmission beyond 80 Mcps. Thus, the first RCG may include a first set or more return link channels, and the second RCG may include a second set or more return link channels that are different from the first set or more return link channels. Based on these first and second RCGs, the scheduler 170 can assign a return link channel with a bandwidth of 160 Mcps to a user terminal 110a communicating via the first beam, according to the first RCG channelization scheme, while the scheduler 170 can assign a return link channel with a bandwidth of only 80 Mcps to a user terminal 110b communicating via the second beam, according to the second RCG channelization scheme. Thus, the scheduler 170 can configure various aspects of the communication system 100a (beams, paths, etc.) in different ways based on and suited to the characteristics of those aspects.

[0043] Based on the allocation from the scheduler 170, each user terminal that is allocated a resource uses the allocated return link channel to transmit data during the allocated period. The schedule for transmitting bursts on the return link may be predetermined by the scheduler 170, at least in part, based on the total demand of user terminals 110a, 110b, and 110c.

[0044] Therefore, the scheduler 170 is configured to receive resource requests (such as requests for return link bandwidth) from each user terminal 110a, 110b, and 110c. For each received resource request, the scheduler 170 is configured to determine the return link channel of the user terminal, at least in part, based on the transmission characteristics of the user terminal. The scheduler 170 is then configured to communicate the determined return link channel, along with the allocated transmit permission period, to the corresponding user terminal.

[0045] The scheduler 170 is configured to determine whether there are overlapping frequency bands and overlapping transmit permission periods in the assigned return link channels. If the scheduler 170 determines that two resource permissions overlap (for example, if the frequency bands overlap at least partially within the overlapping period), the scheduler 170 can reassign one resource permission to another return link channel. This can be repeated until there are no more overlapping resource permissions. The scheduler 170 can be configured to assign resource permissions to different user terminals based on various parameters, including, but not limited to, bandwidth requests, quality of service parameters of a service flow (e.g., priority, guaranteed rate, latency, jitter, etc.), and / or the waiting time for previous resource permissions for the same user terminal or service flow in the scheduler queue. In some embodiments, the scheduler 170 is configured to assign a resource permission to the user terminal at the head of the scheduler queue, and then the scheduler 170 is configured to mark the assigned resource permission (time / frequency resource) as to be used for subsequent assignments. This can reduce or eliminate the need to determine whether allocated resource permissions overlap in terms of time and frequency.

[0046] Subsequently, the scheduler 170 can transmit resource permissions or schedules to user terminals 110a, 110b, and 110c. In some embodiments, the transmitted resource permission grants permission to refer to an index or other identifier of a return link channel to the corresponding user terminal. The user terminal can use the index or other identifier to look up the return link channel in the RCG stored in the user terminal and determine the relevant characteristics of the return link channel to enable the transmission of bursts over the satellite network 140a.

[0047] The scheduler 170 is configured to temporally separate the transmissions of two user terminals when their frequency bands overlap. The scheduler 170 is configured to intelligently schedule transmissions of return link channels that overlap in the frequency domain so that transmissions do not overlap in the time domain. In this way, for a subset of overlapping return link channels (or channels that overlap in frequency bands), only one user terminal can transmit during a given period. Similarly, the scheduler 170 is configured to intelligently schedule transmissions of return channels so that transmission assignments that overlap in the time domain do not overlap in the frequency domain. The scheduler 170 may implement any suitable technology, including but not limited to MF-TDMA technology, to achieve this scheduling.

[0048] The disclosed overlapping channeling technique allows for more efficient use of radio capacity on the return link, which can be particularly beneficial in high-throughput broadband satellite systems. As used herein, overlapping channeling can refer to the existence of return link channels with overlapping frequency bands within a single RCG used by the communication system to allocate transmission resources. Communication systems utilizing overlapping channeling may implement optimization techniques to determine return link channel assignments that do not collide or interfere with each other. This differs from certain channeling techniques that utilize non-overlapping and / or consecutive return link channels, because such techniques do not include return link channels that interfere with each other. The disclosed overlapping channeling technique enables more efficient use of return link capacity by at least partially allocating resources to accommodate the transmission capabilities or needs of user terminals within the system and adapting to changes in those capabilities or needs. Certain channeling techniques do not respond quickly to changes in transmission capabilities or needs because such changes may require implementing and propagating different RCG configurations to user terminals, which can take undesirably long implementation times (e.g., several minutes) and potentially destabilize the network. Furthermore, in certain channelization technologies, the scheduler does not determine that having different channel configurations is beneficial; rather, it selects different RCG channel sets based on predetermined criteria, and changes between sets are made over several minutes. In contrast, the scheduler 170 is configured to determine which channel is appropriate or optimal for each user terminal from all possible channels shown in the overlapping channelization configuration. As a result, different channel configurations can be implemented in real time and reverted to in real time.

[0049] Figure 1B shows another exemplary communication system 100b, which includes an access network 140b configured to connect a plurality of user terminals 110a, 110b communicably to the Internet 160 (or other suitable network) via gateway routing devices 150a, 150b that provide the functions described herein with reference to Figure 1A. The access network 140b can be a terrestrial network, a satellite network, a cellular network, or any combination of these networks. For example, user terminals 110a, 110b may connect to the Internet 160 via the access network 140b which includes a combination of satellite and cellular networks. A scheduler 170 also provides the functions described herein with reference to Figure 1A. In other words, the scheduler 170 allocates transmission resources to user terminals 110a, 110b using an RCG with overlapping return link channels. Thus, the communication system 100b can utilize the overlapping channeling techniques described herein and benefit from the advantages provided by such techniques. The scheduler 170 is also configured to manage transmission resources between user terminals 110a and 110b and gateway routing devices 150a and 150b.

[0050] Figures 2A, 2B, and 2C show an example of scheduling and transmitting bursts according to the resource schedule allocated in the communication system 100a of Figure 1A. Note that a similar procedure can be performed in the communication system 100b of Figure 1B. The procedure for allocating transmission resources in Figures 2A-2C advantageously utilizes the overlapping channeling technique described herein.

[0051] Figure 2A shows that user terminals 110a, 110b, and 110c each request resource authorization 112a, 112b, and 112c on satellite network 140a from scheduler 170 via gateway routing devices 150a and 150b. User terminals 110a, 110b, and 110c request resource authorization from scheduler 170 based on buffer size, quality of service (QoS) parameters, and other flow parameters. Each user terminal 110a, 110b, and 110c has relevant transmission characteristics such as transmission rate. Scheduler 170 can determine the return link channel based at least partially on the transmission characteristics of the user terminals.

[0052] Figure 2B shows that the scheduler 170 allocates resource permissions 230 (time-frequency resources) to one or more time slots, such as time slot 220, in order to respond to resource requests from user terminals 110a, 110b, and 110c. These allocations are based at least in part on the requests from user terminals 110a, 110b, and 110c and the transmission characteristics of user terminals 110a, 110b, and 110c. The allocations can be forwarded to user terminals 110a, 110b, and 110c via gateway routing devices 150a and 150b.

[0053] As shown in Figure 2B, the scheduler 170 is configured to assign resource permissions 230 to time slots 220 in a non-overlapping manner. An overlapping resource permission is one whose frequency overlaps with another resource permission for at least a portion of the time. Here, the scheduler 170 assigns resource permissions 230 in a non-overlapping manner. The scheduler 170 is configured to assign non-overlapping resource permissions even if overlapping channels are defined in the RCG. Assigned resource permissions 230 may use the same or overlapping frequency bands, but reused or overlapping frequency bands are not used in the same period. Similarly, multiple frequency bands can be used in the same period as long as the frequency bands do not overlap. For example, resource permissions 231-234 represent resource permissions to user terminals 110a, 110b, and 110c, where the width of resource blocks 231-234 represents their duration, and the height of resource blocks 231-234 represents their frequency range. Resource permission 231 can be assigned to user terminal 110a, and resource permission 232 can be assigned to user terminal 110c, where resource permissions 231 and 232 are permitted to overlap in time because they span different frequencies. Resource permission 233 can be assigned to user terminal 110a, and resource permission 234 can be assigned to user terminal 110b, where resource permissions 233 and 234 are permitted to overlap in time because they span different frequencies. Furthermore, resource permissions 231 and 234 are permitted to overlap in frequency ranges because they span different time periods. Similarly, resource permissions 232 and 233 are permitted to overlap in frequency ranges because they span different time periods. Further examples of return link channel assignment are described here with reference to Figures 4B, 4C, 5A, and 5B.

[0054] Figure 2C shows how user terminals 110a, 110b, and 110c transmit data 114a, 114b, and 114c from the buffer according to the time-frequency resources allocated by the scheduler 170. Each time-frequency resource corresponds to a return link channel allocated during the transmit permission period, which is selected by the scheduler 170 from the RCG, which contains overlapping return link channels. User terminals 110a, 110b, and 110c transmit data 114a, 114b, and 114c to gateway routing devices 150a and 150b via the return link and satellite network 140a. It is important to understand that multiple gateways (e.g., gateway routing devices 150a and 150b) may be involved in receiving bursts from individual user terminals 110a, 110b, and 110c. After reaching gateway routing devices 150a and 150b, the data is transmitted toward the internet 160. Data from the Internet 160 can be transmitted by gateway routing devices 150a and 150b to user terminals 110a, 110b, and 110c via the forward link of the satellite network 140a. In some embodiments, the scheduler 170 is also configured to manage transmission resources on the forward link of the satellite network 140a, as well as in the way the scheduler manages transmission resources on the return link.

[0055] Example of duplicate channeling As described herein, the disclosed systems and methods provide definitions of return link channel partitions that support overlapping channels. The disclosed communication systems support many different return link channels with different transmission characteristics. A return channel group can be defined to include many or all of the possible return link channels, resulting in overlapping return link channels (or return link channels with overlapping frequencies) within the RCG.

[0056] Figure 3A shows examples of multiple RCGs 301-304, each without overlapping channels, and multiple RCGs 301-304 are configured for use in a particular communication system. Each RCG set 301-304 can define a different RCG and be implemented in different situations. For example, during a rain attenuation event, the communication system may switch from RCG set A301 to RCG set B302, RCG set C303, or RCG set D304 to accommodate the degraded transmission characteristics of the user terminal. However, as described herein, switching from RCG set A301 to any of the other RCG sets 302, 303, or 304 can take an undesirably long time and result in the intermittent unavailability of portions of the spectrum, potentially leading to inefficient use of return link capacity. Another example is when a user terminal enables a higher data rate. To accommodate a user terminal with a higher data rate, RCG set A may be configured as the active RCG. However, if a high-data-rate user terminal is only sporadically using the 160 Mcps channel while RCG set A is active, other user terminals supporting only lower-data-rate channels (e.g., 80 Mcps) cannot use the portion of the spectrum reserved for the 160 Mcps channel, even when the high-data-rate user terminal is idle. In such cases, the entire 160 Mcps frequency band remains unused when the high-data-rate user terminal is not transmitting return link traffic. The disclosed overlapping return link channel technique allows other user terminals to use the portion of the spectrum that might have been reserved for the 160 Mcps channel, thus enabling more efficient use of return link capacity. Therefore, the disclosed technique is configured to use an RCG that includes many or all of the potentially overlapping return link channels, eliminating the need to switch RCGs during operation.

[0057] Figure 3B shows an exemplary RCG300 that provides multiple overlapping return link channels, which are useful in communication systems where transmission characteristics may degrade due to changes in channel conditions (e.g., adverse weather such as rainfall in a satellite network) or in communication systems where one or more dedicated terminals may generate sporadic demands for high-throughput return link traffic. The return link channels are uniquely identified using identifiers id1 to id40. In some embodiments, the identifiers of the return link channels can be used to indicate resource authorization from the scheduler to the user terminal.

[0058] For example, user terminals can transmit using a transmission rate of 80 Mcps under nominal conditions. However, under certain conditions (e.g., rain attenuation events), these same user terminals may not be able to achieve a transmission rate of 80 Mcps, and may only be able to achieve a transmission rate of 40 Mcps or 20 Mcps. The RCG300 enables faster utilization of return link channels by reducing bandwidth. Schedulers such as Scheduler 170 and Scheduler 770 are configured to incorporate authorization into individual return link channels as needed, depending on the channel status in the communication system, and utilize channels with lower transmission rates as necessary.

[0059] For example, the number of user terminals that can transmit at a particular chip rate (e.g., home channel) varies depending on the channel state within the communication system. In clear conditions, most terminals can close the link at the highest chip rate, but during rain attenuation events, many terminals may drop to lower chip rate channels. Furthermore, rain attenuation events may not affect all user terminals in the system uniformly; some terminals may converge to high chip rate channels while others settle at low chip rates. The RCG300 has the advantage of allowing the communication system (e.g., scheduler) to dynamically adapt RCG channeling to user terminals within the communication system, at least partially based on the preferred home channel. The RCG300 also offers a flexible configuration that can be changed in response to changing conditions affecting the performance of user terminals within the communication system. In addition, the RCG300 offers a flexible configuration that can be changed in response to changing demands to accommodate high-throughput return link traffic within the communication system. Furthermore, the RCG400 has the advantage of being able to switch return link channels on a time scale that does not cause network instability.

[0060] Figure 4A shows an example of a return channel group or RCG400 having one return link channel (id9) with a frequency bandwidth that overlaps with the other two return link channels (id8 and id10). Each return link channel in the RCG400 is assigned an index id1 to id10 to uniquely identify it. Note that the index is just one way of identifying a return link channel, and other methods may be employed to identify them. For example, a return link channel can be identified using characteristic frequencies (e.g., center frequency, lower frequency, upper frequency, frequency offset) and bandwidth (e.g., transmission rate, frequency bandwidth, etc.). A return link channel can also be identified or defined using frequency and bandwidth width, e.g., offset from the center frequency of the frequency bandwidth and channel bandwidth (e.g., in Msps or Mcps or MHz units). Identifiers can be used, for example, to identify corresponding return link channels within an RCG when allocating transmit resources or when modifying or updating an RCG. For example, the RCG400 includes 10 return link channels id1 to id10, each with corresponding center frequencies f1 to f10. Each of the return link channels id1 to id10 has a transmission rate of 5 Mcps (id1), 10 Mcps (id2, id3), 40 Mcps (id4, id5), 80 Mcps (id6, id7, id8, and id9), and 160 Mcps (id10).

[0061] RCG400 is an example of an RCG that can be used in a communications system with one or more dedicated terminals that may generate sporadic demand for high-throughput return link traffic. In this example, a dedicated user terminal may be able to maintain a transmission rate of 160 Mcps under nominal conditions. In response to the demand for high-throughput return link traffic, the scheduler (such as scheduler 170 or scheduler 770) can assign return link channel id 10 to a dedicated user terminal with a transmission rate of 160 Mcps. If that user terminal does not require return link bandwidth, it can be assigned return link channels id 8 and id 9, as there is no possibility of transmission burst collisions.

[0062] An example is given to illustrate one or more of the advantages of RCG400. Certain user terminals with low transmission rates (e.g., 5 or 10 Mcps) may not function on return link channels with high transmission rates (e.g., 160 Mcps). In some communication systems with certain RCGs (e.g., RCGs with non-overlapping and / or continuous channeling, as described herein with reference to Figure 3A), a portion of the channeling is reserved for high-throughput user terminals (e.g., 160 Mcps), such as RCG301 in Figure 3A. This portion of channeling may not be available to certain low-transmission-rate user terminals, leaving a significant portion of the available bandwidth unusable when high-throughput user terminals are not transmitting. In the disclosed RCG with overlapping channeling, high-throughput return link channels can be dynamically allocated without reserving a portion of the bandwidth for high-throughput user terminals. This allows low-throughput user terminals to utilize the available bandwidth, since low-throughput return link channels are also defined in an RCG with overlapping channeling (e.g., RCG400). Subsequently, when a high-speed user terminal requests resources for a transmit burst, a high-throughput channel is allocated, and then the use of the low-throughput channel is resumed. Recreating this functionality with a non-overlapping channeling method would require a relatively large number of messages to propagate the RCG changes to the user terminals in the communication system. This is undesirable because, at least in part, the propagation of such changes may be delayed and / or this may cause network instability.

[0063] The RCG400 is configured to enable a 160 Mcps return link channel (id10) on demand for selected terminals. When there is no demand, the use of the return link channel can be reverted to the normal channeling plan (e.g., a maximum transmission rate of 80 Mcps). This allows for a desirable flexible configuration. Furthermore, the disclosed redundant channeling technique prevents network instability due to the dynamic return link channeling timescale. The disclosed redundant channeling technique also reduces capacity loss and equity for non-exclusive terminals.

[0064] Figure 4B shows an exemplary resource authorization map 410 that assigns different user terminals (labeled UT A, UT B, UT C, and UT D) to different return link channels, where the return link channels correspond to the return link channels in RCG400 in Figure 3A (for example, RCG channel id4 in resource authorization map 410 corresponds to channel id4 in RCG400). The horizontal axis represents time, and the allocation block 412 represents each transmit authorization period. If there is no resource allocation, the allocation block displays "GAP". In resource authorization map 410, channels id8 and id9 are allocated during the period covered by resource authorization map 410, and RCG channel id10 is not used because channels id8 and id9 overlap with channel id10 in RCG400. This may represent a situation where a high-capacity dedicated terminal is not requesting or has not been allocated transmit resources. The resource permission maps described herein are similar to UL-MAP messages used in the IEEE 802.16 standard set (e.g., worldwide interoperability for microwave access or WiMAX) used to allocate access to uplink (or downlink) channels. It should be understood that the resource permission maps described herein are simplified to illustrate certain elements of the disclosed technology, but also include other information advantageous or necessary for allocating transmit resources. For example, the disclosed resource permission maps can be configured to conform to the WiMAX standard set of UL-MAPs. Furthermore, it should be understood that the resource permission maps described specify a subset of channels, but also include additional channels where appropriate.

[0065] Figure 4C shows another exemplary resource authorization map 420 that assigns return link channel id 10 to the fifth user terminal (UT E) for a portion of the period covered by resource authorization map 420. This may represent a situation where a high-capacity dedicated terminal requests and is allocated the transmit resource. In resource authorization map 420, RCG channel id 10 is not used in the first period because channels id 8 and id 9 are allocated in the first period, and channels id 8 and id 9 are not used in the second period because channel id 10 is allocated in the second period.

[0066] Figures 4B and 4C illustrate the performance benefits provided by the overlapping channeling technique disclosed herein. Here, the 160 Mcps channel (channel id 10) is selected for high data-rate user terminals (UT E) and is used only when the user terminal has return link traffic. Otherwise, the overlapping 80 Mcps channel can be used for user terminals with compatible transmission rates. The disclosed RCG configuration enables overlapping channeling, so there is no delay in switching between different RCG configurations.

[0067] Figures 5A and 5B show examples of resource authorization maps 510 and 520 that assign resource authorizations by dividing them within time slots (Figure 5A) or by assigning resource authorizations to time slots (Figure 5B). RCG channelization corresponds to RCG400, which is described herein with reference to Figure 4A. Figure 5A shows an in-slot assignment in resource authorization map 510. In resource authorization map 510, since the assignment is divided within time slots, both an 80 Mcps channel and a 160 Mcps channel can burst transmit in the same time slot. In other words, the transmit authorization period can be shorter than the time slot of the communication system and short enough to assign multiple non-overlapping transmit authorization periods to the same time slot. Figure 5B shows an inter-slot assignment in resource authorization map 520. In resource authorization map 520, since two 80 Mcps channels overlap with a 160 Mcps channel, only two 80 Mcps channels or one 160 Mcps channel can have bursts in a given time slot. In other words, the scheduler can make the transmit permission period roughly the same length as the communication system's time slot, so that it cannot assign multiple non-overlapping transmit permission periods to the same time slot.

[0068] Method for allocating transmission resources through duplicate channeling Figure 6 shows a flowchart of an exemplary method 600 for communication in a communication system that supports return channel groups through overlapping channeling. Method 600 can be performed by any of the schedulers described herein with reference to Figures 1A-2C and Figure 7. For simplicity of explanation, Method 600 is described as being performed by a scheduler. This should not be understood as limiting the scope of the disclosure. Rather, any step or part of Method 600 can be performed by any component or any combination of components of the communication system described herein.

[0069] In block 605, the scheduler receives return link bandwidth requests from multiple user terminals. In block 610, the scheduler assigns a return link channel to each requesting user terminal, at least partially based on the transmission characteristics of the corresponding user terminal. The return link channel is selected from multiple return link channels grouped into a return channel group. Each return link channel covers a corresponding frequency band. The scheduler also assigns a transmit permission period to each requesting user terminal. Each of the multiple return link channels within a return channel group has different transmission characteristics, and at least one return link channel has a frequency band that at least partially overlaps with the frequency band of another return link channel. In some embodiments, all possible return link channels of the communication system are included in the return channel group.

[0070] In block 610, the scheduler determines whether the resource allocations assigned in block 605 overlap. To do this, the scheduler determines whether the frequency band of any of the assigned return link channels overlaps at least partially with the frequency band of any of the other assigned return link channels, and whether any of the transmit permission periods overlap at least partially with other transmit permission periods. If the scheduler determines that there are no overlapping allocations, the scheduler communicates the assigned return link channels and associated transmit permission periods to the corresponding user terminal in block 620. In some embodiments, the scheduler is configured to mark resource permissions as acquired as soon as they are assigned, to prevent overlapping resource permissions from being assigned to other user terminals.

[0071] If the scheduler determines that an allocated resource permission has a frequency band and transmit permission period that overlaps with another allocated resource permission, in block 625, it modifies the return link channel and / or transmit permission period for one of the overlapping allocations. The scheduler then returns to block 615 to check if there are any further overlapping allocations. This cycle continues until there are no more overlapping allocations.

[0072] In some embodiments, the scheduler is further configured to periodically send RCG descriptor messages to multiple user terminals, which include updates to the return channel group. The RCG descriptor messages may be configured to add return link channels to the return channel group, adjust the center frequency of the return link channels within the return channel group, and adjust the bandwidth of the return link channels within the return channel group.

[0073] In some embodiments, return link channels are assigned based at least partially on the capabilities of the requesting user terminal (e.g., bandwidth, power). For example, a scheduler may assign a return link channel to a user terminal if its bandwidth is greater than or equal to the transmission rate of the corresponding user terminal. The capabilities of the user terminal may be affected by hardware components such as filters and amplifiers that influence transmission characteristics such as power and bandwidth.

[0074] In some embodiments, the channel state of the communication system degrades the transmission characteristics of one or more of the user terminals. In such situations, the scheduler can assign a return link channel based at least partially on the degraded transmission characteristics. The degraded transmission characteristics may include the transmission rate or duty cycle of the user terminals.

[0075] Example of a scheduler Figure 7 shows a block diagram of an exemplary scheduler 770 configured to allocate resource permissions to multiple user terminals using a return channel group (RCG) with overlapping channeling. This scheduler is similar to scheduler 170 described herein with reference to Figures 1A-2C and can be implemented in any of the communication systems described herein. Scheduler 770 can employ any of the methods described herein for allocating resource permissions using an RCG with overlapping channeling, such as the exemplary method 600 described herein with reference to Figure 6.

[0076] The scheduler 770 may include hardware, software, and / or firmware components for allocating resource permissions. The scheduler 770 includes a datastore 771, one or more processors 773, one or more network interfaces 775, a return link module 772, a schedule conflict module 774, and a forward link module 776. The components of the scheduler 770 can communicate with each other, with external systems, and with other components of the network using a communication bus 779. The scheduler 770 can be implemented using one or more computing devices. For example, the scheduler 770 can be implemented using a single computing device, multiple computing devices, a distributed computing environment, or it can be deployed on a virtual device residing in a public or private computing cloud. In a distributed computing environment, one or more computing devices may be configured to provide modules 772, 774, and 776 to deliver the described functionality.

[0077] The scheduler 770 includes a return link module 772 that assigns return link channels and transmit permission periods to user terminals requesting return link bandwidth. The return link module 772 can be configured to determine a suitable return link channel for a user terminal from a group of return link channels, which may include multiple return link channels with overlapping frequency ranges. The suitability of the return link channel may be based, at least in part, on transmission characteristics such as the transmission rate of the user terminal.

[0078] The scheduler 770 includes a schedule conflict module 774 that analyzes assignments and determines whether assignments conflict with each other. A schedule conflict is an assignment that is assigned to a period in which the frequency band of a first return link channel at least partially overlaps with the frequency band of a second return link channel, and the first and second return link channels at least partially overlap. The schedule conflict module 774 is configured to resolve conflicts by modifying one or more assignments using the return link module 772, and this process may be repeated until there are no more conflicts (e.g., overlapping assignments) in the determined schedule.

[0079] The scheduler 770 includes a forward link module 776 for assigning forward link channels to components requesting forward link bandwidth and transmitting permission periods. The forward link module 776 can be configured to determine a suitable forward link channel from a channel group containing multiple forward link channels with overlapping frequency ranges. The suitability of a forward link channel can be based, at least in part, on transmission characteristics such as the transmission rate of the components or user terminals.

[0080] The scheduler 770 includes one or more processors 773 configured to control the operation of modules 772, 774, 776 and datastore 771. One or more processors 773 implement and use software modules, hardware components, and / or firmware elements configured to allocate resource permissions using RCG with duplicate channeling. One or more processors 773 may include any suitable computer processor, application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or other suitable microprocessor. One or more processors 773 may include other computing components configured to interface with the various modules and datastores of the scheduler 770.

[0081] The scheduler 770 includes a datastore 771 configured to store configuration data, analysis parameters, control commands, databases, algorithms, executable instructions (e.g., instructions for one or more processors 773), etc. The datastore 771 may be any suitable data storage device, or a combination of devices including, but not limited to, random access memory, read-only memory, solid-state disks, hard drives, flash drives, bubble memory, etc.

[0082] Additional embodiments and terminology As used herein, the term “user terminal” may refer to any suitable user equipment that enables communication on the disclosed communication system. Thus, a user terminal may include user equipment or customer premises equipment. As used herein, the terms “resource authorization,” “bandwidth authorization,” and / or “return link authorization” refer to the allocation of transmit resources on the communication system, where resources may include duration and frequency channels. Similarly, as used herein, resource request, bandwidth request, and return link request refer to requests for transmit resources on the communication system.

[0083] As used herein, the term “transmission rate” can be used to refer to the data transmission rate over a network, and may also be called bandwidth, symbol rate, chip rate, bit rate, etc. For example, in direct spread spectrum signals, a “chip” is an encoded element. Mcps is a measure of the speed at which a chip can be generated by a circuit. In digital communications, a chip may refer to a pulse of direct spread spectrum (DSSS) code, for example, a pseudo-random noise (PN) code sequence used in direct code division multiple access (CDMA) channel access technology. In some embodiments, the chip rate and symbol rate are the same and may be used interchangeably herein.

[0084] This disclosure describes various features, none of which, on their own, provide the benefits described herein. It will be understood that the various features described herein can be combined, modified, or omitted, as will be obvious to those skilled in the art. Combinations and subcombinations not specifically described herein will be obvious to those skilled in the art and are intended to form part of this disclosure. This disclosure describes various methods relating to steps and / or phases of various flowcharts. It should be understood that in many cases, certain steps and / or phases can be combined so that multiple steps and / or phases shown in a flowchart can be performed as a single step and / or phase. Also, certain steps and / or phases can be divided into additional subcomponents that are performed separately. In some cases, the order of steps and / or phases can be rearranged, and certain steps and / or phases can be omitted entirely. Furthermore, the methods described herein should be understood to be open-ended, and additional steps and / or phases may be performed in addition to those shown and described herein.

[0085] Some aspects of the systems and methods described herein can be advantageously implemented, for example, using computer software, hardware, firmware, or any combination of computer software, hardware, and firmware. The computer software may include computer executable code stored on a computer-readable medium (e.g., a non-temporary computer-readable medium) that, when executed, performs the functions described herein. In some embodiments, the computer executable code is executed by one or more general-purpose computer processors. Those skilled in the art will understand, in light of this disclosure, that any feature or function that can be implemented using software running on a general-purpose computer can also be implemented using different combinations of hardware, software, or firmware. For example, such a module can be fully implemented in hardware using a combination of integrated circuits. Alternatively or additionally, such features or functions can be fully or partially implemented using a dedicated computer designed to perform the specific functions described herein, rather than a general-purpose computer.

[0086] Instead of any one computing device described herein, multiple distributed computing devices can be used. In such a distributed embodiment, the functions of one computing device are distributed (for example, over a network), and some functions are performed on each distributed computing device.

[0087] Some embodiments can be described with reference to equations, algorithms, and / or flowcharts. These methods can be implemented using computer program instructions executable on one or more computers. These methods can also be implemented separately as computer program products or as components of a device or system. In this regard, each equation, algorithm, block, or step in a flowchart, and combinations thereof, can be implemented by hardware, firmware, and / or software, including one or more computer program instructions embodied in computer-readable program code logic. As will be understood, such computer program instructions can be loaded onto one or more computers, including but not limited to general-purpose computers or dedicated computers, or other programmable processing units for generating machines, and as a result, the computer program instructions executed on the computer or other programmable processing unit implement the functions specified in the equations, algorithms, and / or flowcharts. It should also be understood that each equation, algorithm, and / or block in a flowchart, and combinations thereof, can be implemented by a dedicated hardware-based computer system, or a combination of dedicated hardware and computer-readable program code logic means, to perform the specified functions or steps.

[0088] Furthermore, computer program instructions, for example, those embodied in computer-readable program code logic, are stored in computer-readable memory (e.g., non-temporary computer-readable media), and the instructions stored in computer-readable memory can instruct one or more computers or other programmable processing units to function in a specific way, such that they perform the functions specified in the blocks of a flowchart. The computer program instructions are loaded into one or more computers or other programmable computing devices, a series of operational steps are performed on one or more computers or other programmable computing devices, a computer implementation process is generated, and the instructions executed on the computers or other programmable processing units provide steps for performing the functions specified in the equations, algorithms, and / or blocks of a flowchart.

[0089] Some or all of the methods and tasks described herein are performed by a computer system and are fully automated. The computer system may, in some cases, include multiple separate computers or computing devices (such as physical servers, workstations, and storage arrays) that communicate and interact with each other over a network to perform the functions described. Each such computing device typically includes a processor (or more processors) that executes program instructions or modules stored in memory or other non-temporary computer-readable storage media or devices. While the various functions disclosed herein are embodied in such program instructions, some or all of the disclosed functions may also be implemented in application-specific circuitry (such as ASICs or FPGAs) within the computer system. If the computer system includes multiple computing devices, these devices may, but do not necessarily, be located in the same location. The results of the disclosed methods and tasks can be permanently stored by transforming physical storage devices, such as solid-state memory chips and / or magnetic disks, into different states.

[0090] Unless otherwise clearly indicated in the context, throughout the description and claims, words such as “equipment / includes” and “equipment / includes” shall be interpreted in a comprehensive sense, not exclusive or exhaustive; that is, “includes, but not limited to.” The term “combined” as commonly used herein refers to two or more elements being directly connected or connected via one or more intermediate elements. Furthermore, words such as “in this specification,” “above,” “below,” and similar terms, when used in this application, refer to the entire application and not to any particular part thereof. Where permitted in the context, words used singular or plural in the “detailed description” above may also include plural or singular forms. With respect to the enumeration of two or more items, the word “or” covers all of the following interpretations of the word: any item among the enumerated items, all items within the enumerated items, and any combination of items among the enumerated items. The word “exemplary” is used herein only in the sense of “serving as an example, case, or illustration.” Implementations described as “exemplary” in this specification should not necessarily be interpreted as being preferable or advantageous to other implementations.

[0091] This disclosure is not intended to be limited to the implementations shown herein. Various modifications to the implementations described herein will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other implementations without departing from the spirit or scope of this disclosure. The teachings of this disclosure provided herein can be applied to other methods and systems, and further embodiments can be provided by combining elements and operations of the various embodiments described herein, without limiting them to the above-described methods and systems. Thus, the novel methods and systems described herein can be embodied in various other forms, and furthermore, various omissions, substitutions, and modifications in the form of the methods and systems described herein can be made without departing from the spirit of this disclosure. The accompanying claims and their equivalents are intended to cover forms or modifications that are encompassed within the scope and spirit of this disclosure.

Claims

1. A method of communication in a communication system, wherein the method is Receiving return link bandwidth requests from the first user terminal and the second user terminal, Assigning a first return link channel to the first user terminal based at least in part on the transmission characteristics of the first user terminal, wherein the first return link channel is selected from a plurality of return link channels grouped into a return channel group, and the first return link channel includes a first frequency band. Assigning a first transmission permission period to the first user terminal, Assigning a second return link channel to the second user terminal based at least in part on the transmission characteristics of the second user terminal, wherein the second return link channel is selected from the plurality of return link channels in the return channel group, and the second return link channel includes a second frequency band. Assigning a second transmission permission period to the second user terminal, The first return link channel, the first transmission permission period, the second return link channel, and the second transmission permission period are communicated to the corresponding user terminal. Determining whether the first frequency band overlaps with the second frequency band at least partially, Determining whether the first transmission permission period overlaps at least partially with the second transmission permission period, In response to the determination that the first frequency band at least partially overlaps with the second frequency band and the first transmission permission period at least partially overlaps with the second transmission permission period, a third return link channel is assigned to the first user terminal, wherein the third return link channel has a third frequency band that does not overlap with the second frequency band. Includes, Each of the multiple return link channels within the return channel group has different transmission characteristics, and in these transmission characteristics, at least one return link channel has a frequency band that at least partially overlaps with the frequency band of another return link channel. method.

2. The method according to claim 1, wherein the first user terminal has a different transmission rate than the second user terminal.

3. The method according to claim 1, further comprising assigning a third transmission permission period to the first user terminal in response to a determination that the first frequency band at least partially overlaps with the second frequency band and the first transmission permission period at least partially overlaps with the second transmission permission period, wherein the third transmission permission period does not overlap with the second transmission permission period.

4. The method according to claim 1, wherein communicating the assigned return link channel and transmission permission period to the first and second user terminals is in response to a determination that the first frequency band does not overlap with the second frequency band, or that the first transmission permission period does not overlap with the second transmission permission period.

5. The method according to any one of claims 1 to 4, wherein the return channel group is hardcoded in the first user terminal and the second user terminal.

6. The method according to any one of claims 1 to 4, wherein all possible return link channels of the communication system are included in the return channel group.

7. The method according to any one of claims 1 to 4, wherein each return link channel in the return channel group has a common center frequency.

8. The method according to any one of claims 1 to 4, wherein each return link channel in the return channel group has a common lower end frequency.

9. The method according to any one of claims 1 to 4, further comprising periodically sending return channel group descriptor messages to the first user terminal and the second user terminal, wherein the return channel group descriptor messages include updates to the return channel group.

10. The method according to claim 9, wherein the return channel group descriptor message adds a return link channel to the return channel group, adjusts the center frequency of the return link channel in the return channel group, or adjusts the bandwidth of the return link channel in the return channel group.

11. The method according to any one of claims 1 to 4, wherein the first return link channel has a bandwidth equal to or greater than the transmission rate of the first user terminal, and the second return link channel has a bandwidth equal to or greater than the transmission rate of the second user terminal.

12. The method according to any one of claims 1 to 4, wherein the channel state of the communication system degrades the transmission characteristics of the first user terminal, and the first return link channel is assigned to the first user terminal at least in part based on the degraded transmission characteristics.

13. A communication system that provides communication over a network, wherein the system is A first user terminal having a first maximum bandwidth, the first user terminal configured to store a return channel group including a plurality of return link channels, A second user terminal having a second maximum bandwidth, the second user terminal configured to store the return channel group, The system includes a gateway configured to communicate with the first user terminal and the second user terminal via the network, The aforementioned gateway is The return channel group is stored, Based at least in part on the first maximum bandwidth, a first return link channel from the return channel group, including a first frequency band, is assigned to the first user terminal. A first transmission permission period is assigned to the first user terminal. Based at least partially on the second maximum bandwidth, a second return link channel including a second frequency band is assigned from the return channel group to the second user terminal. A second transmission permission period is assigned to the second user terminal. The first return link channel, the first transmission permission period, the second return link channel, and the second transmission permission period are communicated to the corresponding user terminal. Determine whether the first frequency band overlaps with the second frequency band at least partially. Determine whether the first transmission permission period overlaps with the second transmission permission period, In response to the determination that the first frequency band overlaps at least partially with the second frequency band and the first transmission permission period overlaps at least partially with the second transmission permission period, a third return link channel is assigned to the first user terminal, and the third return link channel has a third frequency band that does not overlap with the second frequency band. It has a scheduler configured as follows: A system in which each of the multiple return link channels within the return channel group has different transmission characteristics, and in the transmission characteristics, at least one return link channel has a frequency band that at least partially overlaps with the frequency band of another return link channel.

14. The communication system according to claim 13, wherein the network includes a satellite network comprising at least one low Earth orbit satellite.

15. The communication system according to claim 13 or 14, wherein the network includes a satellite network comprising at least one medium orbit satellite.

16. The communication system according to claim 13 or 14, wherein the network includes a satellite network comprising at least one geostationary satellite.

17. The communication system according to claim 13 or 14, wherein the network includes a terrestrial network.

18. The communication system according to claim 13 or 14, wherein the network includes a cellular network.

19. The communication system according to claim 13 or 14, wherein the first maximum bandwidth is different from the second maximum bandwidth.

20. The communication system according to claim 13 or 14, wherein the duty cycle of the first user terminal is different from the duty cycle of the second user terminal.

21. The communication system according to claim 13 or 14, wherein the first return link channel is assigned at least in part on channel conditions that reduce the duty cycle of the first user terminal.

22. The communication system according to claim 13 or 14, wherein the first return link channel is allocated based at least in part on channel conditions that reduce the first maximum bandwidth.

23. A scheduler in a communication system, wherein the scheduler is A network interface configured to communicate with a first user terminal and a second user terminal via the aforementioned communication system, A data store configured to store computer executable instructions that generate a return link schedule that allocates the return link bandwidth to the user terminal in response to a request for return link bandwidth from the user terminal, and to store a return channel group that includes multiple return link channels, A processor configured to execute the aforementioned computer executable instructions, and which executes the aforementioned computer executable instructions, A first return link channel from the return channel group, the first return link channel including a first frequency band, is assigned to the first user terminal. A first transmission permission period is assigned to the first user terminal. A second return link channel from the aforementioned return channel group, the second return link channel including a second frequency band, is assigned to the second user terminal. A second transmission permission period is assigned to the second user terminal. The first return link channel, the first transmission permission period, the second return link channel, and the second transmission permission period are communicated to the corresponding user terminal. Determine whether the first frequency band overlaps with the second frequency band at least partially. Determine whether the first transmission permission period overlaps with the second transmission permission period, In response to a determination that the first frequency band at least partially overlaps with the second frequency band and the first transmit permission period at least partially overlaps with the second transmit permission period, a processor assigns a third return link channel to the first user terminal, the third return link channel having a third frequency band that does not overlap with the second frequency band, Equipped with, A scheduler in which the plurality of return link channels within the return channel group each have different transmission characteristics, and in the transmission characteristics, at least one return link channel has a frequency band that at least partially overlaps with the frequency band of another return link channel.

24. The scheduler according to claim 23, wherein, in response to a determination that the first frequency band overlaps at least partially with the second frequency band and the first transmit permission period overlaps at least partially with the second transmit permission period, the processor is further configured to allocate a third transmit permission period to the first user terminal, the third transmit permission period not overlapping with the second transmit permission period.

25. The scheduler according to claim 23 or 24, wherein the processor is configured to communicate the allocated return link channel and transmit permission period to the first and second user terminals in response to a determination that the first frequency band does not overlap with the second frequency band, or that the first transmit permission period does not overlap with the second transmit permission period.

26. The scheduler according to claim 23 or 24, wherein all possible return link channels of the communication system are included in the return channel group.

27. The processor is further configured to periodically send return channel group descriptor messages to the first user terminal and the second user terminal, the scheduler according to claim 23 or 24, wherein the return channel group descriptor messages include updates to the return channel group.

28. The scheduler according to claim 27, wherein the return channel group descriptor message adds a return link channel to the return channel group, adjusts the center frequency of the return link channel in the return channel group, or adjusts the bandwidth of the return link channel in the return channel group.

29. The scheduler according to claim 23, wherein the return channel group is a first return channel group, and the processor is further configured to assign a first return link channel from a second return channel group to a third user terminal, and the second return channel group has a different channeling scheme than the first return channel group.

30. The scheduler according to claim 29, wherein the different channelization scheme of the second return channel group includes a plurality of return link channels different from the plurality of return link channels in the first return channel group.

31. The scheduler according to claim 29 or 30, wherein the processor is further configured to assign one or more of the plurality of return link channels from the first return channel group to user terminals communicating via the first beam in the communication system, and to assign one or more of the plurality of return link channels from the second return channel group to user terminals communicating via the second beam in the communication system.

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