Increasing return link capacity by using overlapping return link channels

Abstract

Described herein are systems and methods that improve or optimize return link capacity by employing overlapping return link channels in a return channel group (RCG) for a communication system shared by a plurality of user terminals. The disclosed techniques enable the simultaneous use of different return link channel configurations while reducing or eliminating the need for additional overhead messaging related to altering the configuration of the RCG. The disclosed techniques allow for more efficient use of return link capacity by responding to changing conditions or requirements in real time.

Description

Background Art Technical Field

[0001] The present disclosure generally relates to allocating transmission resources in a communication system.

[0002] Description of Related Technologies

[0003] Network communication involves sending data back and forth between nodes such as content servers and user terminals. To send user data over the network, a scheduler may be used to allocate network resources to devices, thereby creating a transmission schedule for the devices. Then, based on this schedule, each device can use the allocated resources to transmit data. Based on this schedule, a user terminal can transmit data to a gateway that is part of the communication system for forwarding to a final destination. Summary of the Invention

[0004] In a first aspect, the present 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 a second user terminal. The method further includes allocating a first return link channel to the first user terminal at least partially based on the transmission characteristics of the first user terminal, the first return link channel being selected from a plurality of return link channels grouped together in a return channel group, the first return link channel including a first frequency band. The method further includes allocating a first transmission authorization period to the first user terminal. The method further includes allocating a second return link channel to the second user terminal at least partially based on the transmission characteristics of the second user terminal, the second return link channel being selected from the plurality of return link channels in the return channel group, the second return link channel including a second frequency band. The method further includes allocating a second transmission authorization period to the second user terminal. The method further includes transmitting the first return link channel, the first transmission authorization period, the second return link channel, and the second transmission authorization period to the corresponding user terminals. The plurality of return link channels in the return channel group each have different transmission characteristics, wherein at least one return link channel has a frequency band that at least partially overlaps with the frequency band of another return link channel.

[0005] In some embodiments of the first aspect, the first user terminal has a different transmission rate from the second user terminal.

[0006] In some embodiments of the first aspect, the method further includes determining whether a first frequency band at least partially overlaps with a second frequency band; and determining whether a first transmission authorization period at least partially overlaps with a second transmission authorization period. In further embodiments, the method further includes, in response to determining that the first frequency band at least partially overlaps with the second frequency band and the first transmission authorization period at least partially overlaps with the second transmission authorization period, allocating 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, the method further includes, in response to determining that the first frequency band at least partially overlaps with the second frequency band and the first transmission authorization period at least partially overlaps with the second transmission authorization period, allocating a third transmission authorization period to the first user terminal, wherein the third transmission authorization period does not overlap with the second transmission authorization period. In further embodiments, transmitting the allocated return link channel and transmission authorization period to the first user terminal and the second user terminal is in response to determining that the first frequency band does not overlap with the second frequency band or the first transmission authorization period does not overlap with the second transmission authorization period.

[0007] In some embodiments of the first aspect, a return channel group is hard-coded in the first user terminal and the second user terminal. In some embodiments of the first aspect, all possible return link channels of the communication system are included in the return channel group. In some embodiments of the first aspect, each return link channel in the return channel group has a common center frequency. In some embodiments of the first aspect, each return link channel in the return channel group has a common lower frequency.

[0008] In some embodiments of the first aspect, the method further includes periodically transmitting a Return Channel Group (RCG) descriptor message to the first user terminal and the second user terminal, the RCG descriptor message including an update to the return channel group. In further embodiments, the RCG descriptor message adds a return link channel to the return channel group, adjusts the center frequency of the return link channels in the return channel group, or adjusts the bandwidth of the return link channels in the return channel group.

[0009] In some embodiments of the first aspect, a first return link channel has a bandwidth greater than or equal to the transmission rate of the first user terminal, and a 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 channel conditions of the communication system deteriorate the transmission characteristics of the first user terminal, and the first return link channel is allocated to the first user terminal at least partially based on the deteriorated transmission characteristics.

[0010] In a second aspect, the present disclosure provides a communication system for providing 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 return channel group including a plurality of return link channels. The system further includes a second user terminal having a second maximum bandwidth, the second user terminal being configured to store the return channel group. The system further includes a gateway configured to communicate with the first user terminal and the second user terminal over the network. The gateway includes a scheduler configured to: store the return channel group; allocate a return link channel from the return channel group to the first user terminal at least in part based on the first maximum bandwidth, the first return link channel including a first frequency band; allocate a first transmission authorization period to the first user terminal; allocate a second return link channel from the return channel group to the second user terminal at least in part based on the second maximum bandwidth, the second return link channel including a second frequency band; allocate a second transmission authorization period to the second user terminal; and transmit the first return link channel, the first transmission authorization period, the second return link channel, and the second transmission authorization period to the corresponding user terminals. The plurality of return link channels in the return channel group each have different transmission characteristics, wherein at least one return link channel has a frequency band that at least partially overlaps with the frequency band of another return link channel.

[0011] In some embodiments of the second aspect, the network includes a satellite network having at least one low Earth orbit satellite. In some embodiments of the second aspect, the network includes a satellite network having at least one medium Earth orbit satellite. In some embodiments of the second aspect, the network includes a satellite network having at least one geostationary Earth orbit satellite. In some embodiments of the second aspect, the network includes a terrestrial network. In some embodiments of the second aspect, the network includes a cellular network.

[0012] 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.

[0013] In some embodiments of the second aspect, the first return link channel is allocated at least in part based on channel conditions that reduce the duty cycle of the first user terminal. In some embodiments of the second aspect, the first return link channel is allocated at least in part based on channel conditions that reduce the first maximum bandwidth.

[0014] In a third aspect, the present 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 further includes a data memory configured to store computer-executable instructions for generating a return link schedule that allocates return link bandwidth to user terminals in response to requests for return link bandwidth from the user terminals, and to store a return channel group including a plurality of return link channels. The scheduler further includes a processor configured to execute the computer-executable instructions to perform the following operations: allocate a first return link channel from the return channel group to the first user terminal, the first return link channel including a first frequency band; allocate a first transmission authorization period to the first user terminal; allocate a second return link channel from the return channel group to the second user terminal, the second return link channel including a second frequency band; allocate a second transmission authorization period to the second user terminal; and transmit the first return link channel, the first transmission authorization period, the second return link channel, and the second transmission authorization period to the corresponding user terminals. Each of the plurality of return link channels in the return channel group has different transmission characteristics, wherein at least one return link channel has a frequency band that at least partially overlaps with the frequency band of another return link channel.

[0015] In some embodiments of the third aspect, the processor is further configured to perform the following operations: determine whether the first frequency band at least partially overlaps with the second frequency band; and determine whether the first transmission authorization period at least partially overlaps with the second transmission authorization period. In a further embodiment, in response to determining that the first frequency band at least partially overlaps with the second frequency band and the first transmission authorization period at least partially overlaps with the second transmission authorization period, the processor is further configured to allocate 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. In a further embodiment, in response to determining that the first frequency band at least partially overlaps with the second frequency band and the first transmission authorization period at least partially overlaps with the second transmission authorization period, the processor is further configured to allocate a third transmission authorization period to the first user terminal, wherein the third transmission authorization period does not overlap with the second transmission authorization period. In a further embodiment, the processor is configured to transmit the allocated return link channels and transmission authorization periods to the first user terminal and the second user terminal in response to determining that the first frequency band does not overlap with the second frequency band or the first transmission authorization period does not overlap with the second transmission authorization period.

[0016] In some embodiments of the third aspect, all possible return link channels of the communication system are included in the return channel group.

[0017] In some embodiments of the third aspect, the processor is further configured to periodically transmit RCG descriptor messages to the first user terminal and to the second user terminal, the RCG descriptor messages including an update to a return channel group. In further embodiments, the RCG descriptor messages add a return link channel to the return channel group, adjust a center frequency of a return link channel in the return channel group, or adjust a bandwidth of a return link channel in the return channel group.

[0018] For purposes of summarizing the disclosure, certain aspects, advantages, and novel features have been described herein. It is to be understood that not all such advantages may be achieved in accordance with any particular embodiment. Accordingly, the disclosed embodiments may be implemented or carried out in a manner that realizes or optimizes one advantage or a group of advantages taught herein without necessarily realizing other advantages taught or suggested herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] For purposes of illustration, various embodiments are depicted in the drawings and should not be construed as limiting the scope of the disclosure. Additionally, various features of the disclosed different embodiments may be combined to form additional embodiments that are part of the disclosure.

[0020] Figure 1A A diagram showing an example communication system that uses a satellite network and a scheduler to provide and manage communication between multiple user terminals and multiple gateway routing devices to provide access to a network such as the Internet.

[0021] Figure 1B Another example communication system is shown that includes an access network and a scheduler to provide and manage communication between multiple user terminals and multiple gateway routing devices to provide access to the Internet (or other suitable network).

[0022] Figure 2A Each of the user terminals is shown requesting resource authorization on the satellite network from the scheduler via a gateway routing device.

[0023] Figure 2B The scheduler is shown allocating resource blocks (time-frequency resources) in one or more time slots to serve resource requests from the user terminals.

[0024] Figure 2C The user terminals are shown transmitting data from their buffers according to the time-frequency resources allocated by the scheduler.

[0025] Figure 3A An example of multiple return channel groups (RCGs) is shown, each return channel group not including overlapping return link channels, the multiple RCGs being configured for use in certain communication systems.

[0026] Figure 3B An example RCG channelization that provides an overlapping return link channel is shown, thereby providing enhanced functionality relative to the Figure 3A RCG channelization set.

[0027] Figure 4A An example of an RCG with one return link channel is shown, where the return link channel has a frequency band that overlaps with two other return link channels.

[0028] Figure 4B An example resource authorization mapping that assigns different user terminals to different return link channels is shown, where the return link channels correspond to the return link channels in the Figure 4A RCG.

[0029] Figure 4C Another example resource authorization mapping is shown.

[0030] Figure 5A An in-slot assignment within a resource authorization mapping is shown.

[0031] Figure 5B An inter-slot assignment within a resource authorization mapping is shown.

[0032] Figure 6 A flowchart of an example method of communicating on a communication system that supports a return channel group with overlapping channelization is shown.

[0033] Figure 7 A block diagram of an example scheduler configured to allocate resource authorizations to multiple user terminals using an RCG with overlapping channelization is shown. DETAILED DESCRIPTION

[0034] The section headings provided herein (if any) are for convenience only and need not affect the scope or meaning of the claimed embodiments.

[0035] Overview

[0036] A communication system can communicate with multiple terminals simultaneously on both the 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 transmit data simultaneously on the return link and / or receive data on 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 in turn is limited by the available system resources.

[0037] Various reverse link channels can be defined to manage transmissions from user terminals on a communication system. The reverse link channels can be defined by suitable transmission characteristics such as characteristic frequencies (e.g., center frequency, lower frequency, upper frequency, frequency offset, etc.) and bandwidth (e.g., transmission rate). The reverse link channels can be defined to accommodate a particular transmission rate (e.g., symbol rate or chip rate). Thus, a user terminal can be allocated transmission resources by requesting resources and being assigned a reverse link channel for reverse link transmission during a transmission authorization period.

[0038] In some embodiments, multiple reverse link channels can be grouped into a reverse channel group (RCG). The RCG can include multiple reverse link channels to provide reverse link channels for various transmission rates. In an RCG shared by multiple user terminals, the reverse link channels can be defined as contiguous and non-overlapping to reduce or minimize interference and increase or maximize capacity. The RCG defined in this way can minimize interference at least in part because the frequency bands of the reverse link channels do not overlap with each other, and can maximize capacity at least in part because the frequency bands are contiguous (e.g., the frequency bands of the reverse link channels are adjacent to each other).

[0039] The transmission resources on the reverse link are allocated to user terminals using the reverse link channels from the RCG. The RCG can be transmitted to the user terminals using messaging (e.g., an RCG descriptor message), which propagates throughout the communication system a description of the set of reverse link channels for the RCG. The messaging for transmitting the RCG can be accomplished using any suitable broadcast message that the communication system can use to transmit system information related to reverse link allocation to multiple user terminals.

[0040] If one wishes to use an RCG with non-overlapping return link channels having a different permutation (e.g., to accommodate the emergence of high data rate user terminals or due to a rain fade event), then the change in the channel permutation must be propagated throughout the communication system, which may take an undesirably long time (e.g., several minutes) to complete. This delay is caused by the process used to update the RCG, where the process may involve network components (e.g., a scheduler) determining that changing the RCG would be beneficial based on user traffic demands or changing channel conditions. Then, the process involves propagating the RCG to the user terminals using some over-the-air (OTA) message. Other components in the network (e.g., physical layer processing modules) may also require the updated RCG information to reconfigure their components using the new channelization profile. The process may also include the user terminals adjusting their transmission chains to accommodate the new RCG. For example, the user terminals may need to improve their physical layer control loops to optimize their transmission parameters on the newly defined RCG. These steps in the process may also require one or more round trips over the wireless link. For example, for a geostationary satellite link, the process may take an undesirably long time and may exceed several minutes. This makes it challenging to respond quickly to changing conditions in the communication network that may affect the effectiveness or applicability of the current RCG.

[0041] For example, a situation may arise where the channel conditions may deteriorate (e.g., rain may adversely affect the transmission capabilities in a satellite communication system). In such a case, it may be necessary to use a different RCG that includes more return link channels to achieve a lower transmission rate than that defined in the current RCG. This can be done to accommodate user terminals that drop to a lower transmission rate under such conditions. Otherwise, bandwidth may be allocated to user terminals that cannot utilize all the allocated bandwidth due to the deteriorating channel conditions, resulting in reduced efficiency of the communication system. As another example, high-capacity user terminals may generate sporadic demands for higher throughput return link traffic. In such a case, it may be necessary to use a different RCG that includes available return link channels for a higher transmission rate that may not be defined in the current RCG. Otherwise, there is unused transmission capacity in the communication system.

[0042] In situations similar to these, it may take an undesirably long time to propagate different RCGs to user terminals and other components of a communication system, as described herein. Accordingly, described herein are systems and methods that improve or optimize return link capacity by employing overlapping return link channels in an RCG for a communication system shared by multiple user terminals. The disclosed techniques enable the simultaneous use of different return link channel configurations while reducing or eliminating the need for additional overhead messaging associated with changing the RCG. The disclosed techniques allow for more efficient use of return link capacity by responding in real time to changing conditions or requirements.

[0043] The disclosed systems and methods specify multiple return link channels in a communication system and define an RCG to include each of these channels, where two or more of the channels overlap in frequency. In some embodiments, the RCG includes every possible return link channel in the communication system. In various implementations, the return link channels are defined in the RCG to have unique channel identifiers and frequency offsets. In some embodiments, the RCG may be hard-coded in the user terminals and in the code at a scheduler or other component such as a base station or a ground station. In certain embodiments, a periodic message is transmitted with a list of all channels in the RCG, including the overlapping channels. In such an embodiment, the user terminals read the message to understand the return link channelization defined by the communication system. Doing so allows for flexibility in the communication system to change the channelization, which may be beneficial as the network evolves and new channels are introduced.

[0044] Because the channels overlap in the disclosed RCG, not all of the channels defined in the RCG can be used simultaneously. Accordingly, a scheduler or other component in the communication system is configured to ensure that user terminals are scheduled in a non-overlapping manner. Non-overlapping time-frequency assignments avoid co-channel interference in certain communication systems, such as those employing multi-frequency time division multiple access (MF-TDMA). For example, if a user terminal is scheduled to transmit on a first channel during a first time period, the scheduler is configured not to allow any other user terminal to transmit on a channel having a frequency band that overlaps the frequency band of the first channel during a time period that overlaps the first time period.

[0045] Advantageously, at least in part because the disclosed RCGs include many or all of the possible channel configurations available in a communication system, the disclosed techniques can eliminate the need for channel reconfiguration algorithms or messaging. Advantageously, the disclosed techniques also allow terminals of different capabilities to coexist in a communication system. For example, a terminal capable of transmitting at 160 Mcps (megachips per second) can coexist with a terminal that can transmit at most 10 Mcps with little or no bandwidth waste. Additionally, the disclosed techniques advantageously enable different combinations of communication performance to exist and be active simultaneously on different aspects of a communication system. For example, a first beam of a satellite can employ channelization capable of transmitting at 160 Mcps, while another beam of the satellite does not include channelization capable of transmitting at 160 Mcps.

[0046] Example Communication System

[0047] Figure 1A FIG. shows an example communication system 100a that uses a satellite network 140a to communicatively couple a plurality of user terminals 110a, 110b, 110c and a plurality of gateway routing devices 150a, 150b to each other to provide access to a network such as the Internet 160. The communication system 100a includes a scheduler 170 configured to allocate resource grants to the user terminals 110a, 110b, 110c. The communication system 100a includes a plurality of gateway satellite transceivers 130a, 130b and a plurality of customer satellite transceivers 120a, 120b, 120c configured to transmit and receive signals via a satellite 105.

[0048] The communication system 100a can utilize various network architectures including a space segment and a ground segment. The satellite network 140a combines these elements to provide communication between the plurality of user terminals 110a, 110b, 110c and the gateway routing devices 150a, 150b. For example, the space segment can include one or more satellites, and the ground segment can include one or more satellite user terminals, gateway terminals, a network operations center (NOC), satellite and gateway terminal command centers, and / or the like. Some of these elements are not shown in the figure for clarity. The satellite network 140a can include one or more geostationary earth orbit (GEO) satellites, one or more medium earth orbit (MEO) satellites, and / or one or more low earth orbit (LEO) satellites. It should be understood that the satellite 105 can represent one or more satellites, and the one or more satellites can include GEO satellites, MEO satellites, LEO satellites, or any combination of these satellites.

[0049] User terminals 110a, 110b, 110c may include routers or other user equipment and may be configured to send and receive data routed through communication system 100a. User terminals 110a, 110b, 110c may include or be communicatively coupled to any type of customer premise equipment (e.g., telephone, modem, router, computer, set-top box, etc.). User terminals 110a, 110b, 110c are configured to send and receive data via respective customer satellite transceivers 120a, 120b, 120c using satellite network 140a. Customer satellite transceivers 120a, 120b, 120c may include an antenna that is a phased array, two antennas (e.g., one for transmission and one for reception), or multiple antennas each accessing a different satellite or communication path.

[0050] Satellite network 140a provides a forward link for routing information from gateway routing devices 150a, 150b to user terminals 110a, 110b, 110c and a return link for routing information from user terminals 110a, 110b, 110c to gateway routing devices 150a, 150b. The forward link and return link may be referred to as over-the-air (OTA) signals or communication paths. The forward link includes a transmission path that goes from gateway routing devices 150a, 150b through respective gateway satellite transceivers 130a, 130b, via a satellite uplink channel through satellite 105, via a satellite downlink channel to customer satellite transceivers 120a, 120b, 120c and to user terminals 110a, 110b, 110c. The return link includes a transmission path that goes from user terminals 110a, 110b, 110c through respective customer satellite transceivers 120a, 120b, and 120c, via a satellite uplink channel through satellite 105, via a satellite downlink channel to gateway satellite transceivers 130a, 130b, and to gateway routing devices 150a, 150b. It should be understood that each communication path may utilize multiple satellites and transceivers.

[0051] Scheduler 170 is configured to manage the allocation of communication resources to user terminals 110a, 110b, 110c. Scheduler 170 may be part of gateway routing devices 150a, 150b, or it may be a separate component of communication system 100a. Additionally, communication resources may be managed by multiple components of communication system 100a. In some embodiments, part or all of gateway routing devices 150a, 150b and / or scheduler 170 may be located in virtual devices residing in a public or private computing cloud and / or as part of a distributed computing environment. Scheduler 170 may be configured to manage resources for multiple gateway routing devices 150a, 150b as well as user terminals 110a, 110b, 110c.

[0052] In some embodiments, one or more of user terminals 110a, 110b, 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 Long Term Evolution (LTE) technology; and / or terrestrial systems such as Digital Subscriber Line (DSL) using different customer satellite transceivers 120a, 120b, 120c). Thus, for user terminals 110a, 110b, 110c, there may be multiple communication paths between the user terminal and the Internet 160. In some embodiments, communication system 100a (e.g., scheduler 170) is configured to select a desired, efficient, or optimal communication path for user terminals 110a, 110b, 110c among the multiple communication paths available to the user terminal.

[0053] As described herein, return link channels are grouped into Return Channel Groups (RCGs). The RCGs disclosed herein include multiple return link channels, where at least one return link channel has a frequency band that overlaps with another return link channel. In some embodiments, the RCGs disclosed herein explicitly list many or all of the possible return link channels available for communication system 100a. A communication system such as communication system 100a has a limited number of channels that can be used in the system, where the number of channels depends on various system limitations such as quantization of time and frequency, the numerology of the system, etc. In certain implementations, 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 an authorized spectrum, which is uniquely determined by its frequency range (e.g., parameterized by a lower frequency, an upper frequency, and a channel bandwidth). Given a frequency band, a simple channelization scheme for the return link channels within the RCG may involve some parameters such as a minimum channel bandwidth and a scaling factor. In such a channelization scheme, each possible return link channel has a bandwidth of the form BW_min*SF^n Mcps, where BW_min is the minimum channel bandwidth, SF is the scaling factor, and n is a non-zero positive integer. Thus, the set of all possible return link channels for a given scheme can be determined.

[0054] As a specific example, a communication system may use a 500 MHz channel in the Ka band spanning a frequency range of 21.0 GHz to 21.5 GHz, where the minimum channel bandwidth (BW_min) is 5 Mcps and the scaling factor (SF) is 2. The possible return link channels in this scenario have a bandwidth of the form 5 * 2^n Mcps. Since the RCG spans a maximum bandwidth of 500 MHz, the maximum return link channel bandwidth can be 320 Mcps. In other words, for this channelization scheme, the possible return channel bandwidths are 5, 10, 20, 40, 80, 160, and 320 Mcps. Considering the bandwidth of the frequency range, the set of all possible return link channels for this scheme includes 100 possible 5 Mcps channels, 50 possible 10 Mcps channels, 25 possible 20 Mcps channels, 12 possible 40 Mcps channels, 6 possible 80 Mcps channels, 3 possible 160 Mcps channels, and 1 possible 320 Mcps channel. In some embodiments, overlapping channels of different bandwidths may have a common lower frequency limit. In various embodiments, overlapping channels may have a common center frequency.

[0055] In some embodiments, the RCG is hard - coded in the scheduler 170 and the user terminals 110a, 110b, 110c. In some embodiments, the RCG can be changed by the scheduler 170, and the change to the RCG can be communicated to the user terminals 110a, 110b, 110c and other components of the communication system 100a via an RCG descriptor message.

[0056] The scheduler 170 is configured to use the RCG to allocate transmission resources on the return link to user terminals 110a, 110b, 110c. For example, for each user terminal 110a, 110b, 110c that requests bandwidth on the return link, the scheduler 170 allocates a transmission authorization 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 at least in part based on the transmission characteristics of the respective user terminal. For example, the return link channel may be configured to accommodate a particular transmission rate (e.g., symbol rate or chip rate), and the scheduler 170 may be configured to allocate the return link channel to a user terminal that is capable of achieving the particular transmission rate supported by the return link channel. For example, the scheduler 170 may be configured to allocate a return link channel with a bandwidth that accommodates a transmission rate of 80 Mcps to a user terminal that is capable of transmitting at 80 Mcps. The performance of the user terminal is affected by the hardware components of the user terminal (such as filters and amplifiers), which affect transmission characteristics (such as power and bandwidth). The performance of the user terminal is also associated with parameters of the user terminal, such as maximum power or terminal antenna performance / off-axis, etc. The scheduler 170 is thus configured to allocate a return link channel at least in part based on the performance of the respective user terminal, which is affected by components that affect transmission characteristics.

[0057] In some embodiments, the scheduler 170 may allocate different RCGs to different aspects of the communication system 100a, such as the satellite network 140a. For example, the scheduler 170 may allocate a first RCG with a first channelization scheme to a first communication link (e.g., beam) of the communication system 100a, and allocate a second RCG with a second channelization scheme different from the first channelization scheme to a second communication link. Different RCGs with different channelization schemes may enable different devices to communicate simultaneously via their respective communication links.

[0058] For example, the first beam of satellite network 140a can serve one or more user terminals 110 (fixed and / or mobile) capable of transmitting at 80 Mcps and 160 Mcps, and can allocate to them a first RCG adopting a first channelization scheme capable of device communication at both 80 and 160 Mcps. However, the second beam of satellite network 140a can serve one or more user terminals 110 (fixed and / or mobile) capable of transmitting at a maximum of 80 Mcps, and can allocate to them a second RCG adopting a second channelization scheme that cannot perform device transmission at greater than 80 Mcps. In this way, the first RCG can include a first set or multiple return link channels, and the second RCG can include a second set or multiple return link channels different from the first set or multiple return link channels. Based on these first RCG and second RCG, the scheduler 170 can allocate a return link channel with a bandwidth adapted to 160 Mcps to the user terminal 110a communicating via the first beam according to the first RCG channelization scheme, while the scheduler 170 allocates a return link channel with a bandwidth only adapted to 80 Mcps to the user terminal 110b communicating via the second beam according to the second RCG channelization scheme. Therefore, the scheduler 170 can configure various aspects (such as beams, paths, etc.) of the communication system 100a in different ways according to and adapting to the characteristics of those aspects of the communication system 100a.

[0059] Based on the allocation from the scheduler 170, each user terminal that has been allocated resources uses the allocated return link channel to transmit data during the allocated period. The scheduler 170 can determine in advance the schedule of burst transmissions on the return link at least partially based on the aggregated requirements of the user terminals 110a, 110b, 110c.

[0060] Therefore, the scheduler 170 is configured to receive resource requests (such as requests for return link bandwidth) from each of the user terminals 110a, 110b, 110c. For each received resource request, the scheduler 170 is configured to determine the return link channel for the user terminal at least partially based on the transmission characteristics of the user terminal. Then, the scheduler 170 is configured to transmit the determined return link channel together with the specified transmission authorization period to the corresponding user terminal.

[0061] The scheduler 170 is configured to determine whether any of the allocated return link channels have overlapping frequency bands and overlapping transmission authorization periods. If the scheduler 170 determines that two resource authorizations overlap (e.g., the frequency bands overlap at least partially during at least partially overlapping periods), the scheduler 170 may reallocate one of the resource authorizations to a different return link channel. This may be repeated until there are no overlapping resource authorizations. The scheduler 170 may be configured to allocate resource authorizations to individual user terminals based on a variety of parameters such as, for example, but not limited to, bandwidth requests, quality of service parameters of the service flow (e.g., priority, guaranteed rate, latency, jitter, etc.), and / or the waiting time of previous resource authorizations for the same user terminal or service flow in the scheduler queue. In some embodiments, the scheduler 170 is configured to allocate resource authorizations to user terminals at the head of the scheduler queue, and the scheduler 170 is then configured to mark the allocated resource authorizations (time / frequency resources) for subsequent allocation. This may reduce or eliminate the need to determine whether the allocated resource authorizations overlap in time and frequency.

[0062] The scheduler 170 may then allocate resource authorizations or schedule transmissions to user terminals 110a, 110b, 110c. In some embodiments, the transmitted resource authorizations reference an index or other identifier of the return link channel of the corresponding user terminal. The user terminal may use the index or other identifier to look up the return link channel in the RCG stored at the user terminal to determine the relevant characteristics of the return link channel, enabling bursty transmissions over the satellite network 140a.

[0063] The scheduler 170 is configured to separate the transmissions of two user terminals in time if their frequency bands overlap. The scheduler 170 is configured to intelligently schedule the transmissions of return link channels that overlap in the frequency domain such that the transmissions do not overlap in the time domain. In this way, only one user terminal is allowed to transmit during the periods of a subset of the overlapping return link channels (or channels that overlap in the frequency band). Similarly, the scheduler 170 is configured to intelligently schedule the transmissions of the return channels such that the transmission allocations that overlap in the time domain do not overlap in the frequency domain. The scheduler 170 may perform any suitable technique to accomplish this scheduling, including but not limited to MF-TDMA techniques.

[0064] The disclosed overlapping channelization techniques enable more efficient use of the air capacity on the return link, which can be particularly beneficial for high-throughput broadband satellite systems. As used herein, overlapping channelization may refer to the presence of return link channels with overlapping frequency bands within a single RCG used by a communication system to allocate transmission resources. In a communication system that utilizes overlapping channelization, optimization schemes can be implemented to determine return link channel allocations that do not conflict or interfere with each other. This is different from some channelization schemes that utilize non-overlapping and / or sequential return link channels, as such schemes do not include return link channels that interfere with each other. The disclosed overlapping channelization techniques enable more efficient use of the return link capacity at least in part due to the ability to allocate resources corresponding to the transmission capabilities or requirements of user terminals in the system and to adapt to changes in those transmission capabilities or requirements. Some channelization techniques cannot respond quickly to changing transmission capabilities or requirements because such changes may require implementing different RCG configurations and propagating them to user terminals, which may take an undesirably long time (e.g., several minutes) to implement and may result in network instability. Additionally, with some channelization techniques, the scheduler does not decide that having different channel configurations is beneficial, but instead selects different sets of RCG channels based on a predetermined criterion, and the change between sets occurs within minutes. In contrast, the scheduler 170 is configured to determine which channel is appropriate or optimal for each respective user terminal, and this selection is made from all of the possible channels indicated in the overlapping channelization configuration. Thus, different channel configurations can be implemented in real time and can also be recovered in real time.

[0065] Figure 1B Another example communication system 100b is shown that includes an access network 140b, which is configured to communicatively couple a plurality of user terminals 110a, 110b to the Internet 160 (or other suitable network) via gateway routing devices 150a, 150b that provide the functionality described herein with reference Figure 1A to. 1A. The access network 140b can be a terrestrial network, a satellite network, a cellular network, or any combination of these networks. For example, the user terminals 110a, 110b can be coupled to the Internet 160 via an access network 140b that includes a combination of a satellite network and a cellular network. The scheduler 170 also provides the functionality described herein with reference Figure 1A to. In other words, the scheduler 170 utilizes an RCG with overlapping return link channels to allocate transmission resources to the user terminals 110a, 110b. Thus, the communication system 100b can utilize the overlapping channelization techniques described herein and can benefit from the advantages provided by such techniques. The scheduler 170 is also configured to manage the transmission resources between the user terminals 110a, 110b and the gateway routing devices 150a, 150b.

[0066] Figure 2A 、2B Figures 1A and 2C illustrate an example of scheduling and transmitting a burst according to allocated resource scheduling in a Figure 1A communication system 100a. 1A. It should be noted that a similar process can be implemented in a Figure 1B communication system 100b. 1B. Figures 2A to 2C The process of allocating transmission resources in

[0067] Figure 2A Figures 1A and 2C shows that each of user terminals 110a, 110b, 110c requests resource authorizations 112a, 112b, 112c on satellite network 140a from scheduler 170 via gateway routing devices 150a, 150b. User terminals 110a, 110b, 110c request resource authorizations from scheduler 170 based on buffer size, quality of service (QoS) parameters, and other flow parameters. Each of user terminals 110a, 110b, 110c has an associated transmission characteristic, such as a transmission rate. Scheduler 170 can determine the return link channel at least in part based on the transmission characteristics of the user terminals.

[0068] Figure 2B Figure 1B shows that scheduler 170 allocates resource authorizations 230 (time-frequency resources) in one or more time slots, such as time slot 220, to serve the resource requests from user terminals 110a, 110b, 110c. These allocations are at least in part based on the demands from user terminals 110a, 110b, 110c and the transmission characteristics of user terminals 110a, 110b, 110c. The allocations can be transmitted to user terminals 110a, 110b, 110c via gateway routing devices 150a, 150b.

[0069] As Figure 2BAs shown, scheduler 170 is configured to allocate resource grant 230 in time slot 220 such that there is no overlap. An overlapping resource grant would be a resource grant that overlaps at least partially in frequency with another resource grant for at least a portion of the time period. Here, scheduler 170 allocates resource grant 230 such that there is no overlap. Even if overlapping channels are defined in the RCG, scheduler 170 is configured to allocate non-overlapping resource grants. The allocated resource grants 230 may use the same or overlapping frequency bands, but the multiplexed or overlapping frequency bands are not used during the same time period. Similarly, multiple frequency bands may be used within the same time period as long as the frequency bands do not overlap. For example, resource grants 231 to 234 represent resource grants for user terminals 110a, 110b, 110c, where the width of resource blocks 231 to 234 represents their duration and the height of resource blocks 231 to 234 represents their frequency span. Resource grant 231 may be allocated to user terminal 110a, and resource grant 232 may be allocated to user terminal 110c, where resource grants 231, 232 are allowed to overlap in time because they span different frequencies. Resource grant 233 may be allocated to user terminal 110a, and resource grant 234 may be allocated to user terminal 110b, where resource grants 233, 234 are allowed to overlap in time because they span different frequencies. Additionally, resource grants 231, 234 are allowed to have overlapping frequency ranges because they span different time periods. Similarly, resource grants 232, 233 are allowed to have overlapping frequency ranges because they span different time periods. Further examples of return link channel allocation are described herein with reference to Figure 4B , 4C , 5A and 5B.

[0070] Figure 2CIt is shown that user terminals 110a, 110b, 110c transmit data 114a, 114b, 114c from their buffers according to time-frequency resources allocated by scheduler 170. Separate time-frequency resources correspond to return link channels allocated during a transmission authorization period, where the return link channels are selected from an RCG at scheduler 170, and the RCG includes overlapping return link channels. User terminals 110a, 110b, 110c route data 114a, 114b, 114c to gateway routing devices 150a, 150b via a return link through satellite network 140a. It should be understood that multiple gateways (e.g., gateway routing devices 150a, 150b) may be involved when receiving bursts from respective user terminals 110a, 110b, 110c. After reaching gateway routing devices 150a, 150b, the data can then be directed to Internet 160. Data from Internet 160 can be sent by gateway routing devices 150a, 150b to user terminals 110a, 110b, 110c via the forward link of satellite network 140a. In some embodiments, scheduler 170 is also configured to manage transmission resources on the forward link of satellite network 140a, similar to the way the scheduler manages transmission resources on the return link.

[0071] Example of Overlapped Channelization

[0072] As described herein, the disclosed systems and methods provide for defining return link channel partitions and for supporting overlapping channels. The disclosed communication system supports many different return link channels with different transmission characteristics. A return channel group can be defined to include many or all possible return link channels, which results in overlapping return link channels in the RCG (or return link channels with frequency overlap).

[0073] Figure 3AIllustrates examples of multiple RCGs 301 to 304, each of which does not include overlapping channels, and the multiple RCGs 301 to 304 are configured for use in certain communication systems. Each set of RCGs 301 to 304 defines a different RCG and can be implemented in different situations. For example, during a rain fade event, the communication system can switch from RCG set A 301 to RCG set B 302, RCG set C 303, or RCG set D 304 to adapt to the deteriorated transmission characteristics of the user terminal. However, as described herein, changing from RCG set A 301 to any of the other RCG sets 302, 303, 304 may take an undesirably long time and may result in inefficient use of the return link capacity because it intermittently makes a portion of the spectrum unavailable. As another example, there may be user terminals capable of having a higher data rate. To accommodate user terminals with a higher data rate, RCG set A can be set as the active RCG. However, when RCG set A is activated, if the high data rate user terminal only occasionally uses the 160 Mcps channel, other user terminals that only support lower data rate channels (e.g., 80 Mcps) cannot use a portion of the spectrum reserved for the 160 Mcps channel even when the high data rate user terminal is idle. In this case, when the high data rate user terminal does not send return link traffic, the entire 160 Mcps band remains unused. With the disclosed overlapping return link channel scheme, other user terminals can use a portion of the spectrum that could have been reserved for the 160 Mcps channel, thus more efficiently utilizing the return link capacity. Therefore, the disclosed technology is configured to utilize RCGs that include many or all possible return link channels that may overlap to avoid the need to switch between RCGs during operation.

[0074] Figure 3B Illustrates an example RCG 300 that provides many overlapping return link channels, which can be used in a communication system where transmission characteristics may deteriorate due to changes in channel conditions (e.g., adverse weather such as rain in a satellite network) and / or 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 identifier of the return link channel can be used to indicate resource authorization from the scheduler to the user terminal.

[0075] For example, a user terminal can transmit at a transmission rate of 80 Mcps under nominal conditions. However, when certain conditions occur (e.g., a rain fade event), 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 RCG 300 allows for the rapid utilization of the return link channel and reduces the bandwidth. A scheduler such as scheduler 170 or scheduler 770 is configured to schedule authorizations on respective return link channels as appropriate based on the channel conditions in the communication system, thereby utilizing more of the lower transmission rate channels at the appropriate time.

[0076] For example, the number of user terminals capable of transmitting at a specific chip rate (e.g., the home channel) varies with the channel conditions in the communication system. Under clear sky conditions, most terminals may be able to turn off the link with the highest chip rate, but during a rain fade event, many terminals may fall into lower chip rate channels. Additionally, a rainfall event may not affect all user terminals in the system uniformly, with some terminals congregating on higher chip rate channels while others select lower chip rate channels. The RCG 300 advantageously allows the communication system (e.g., the scheduler) to dynamically adjust the RCG channelization to accommodate user terminals in the communication system based at least in part on the preferred home channels of the user terminals. The RCG 300 also provides a flexible configuration that can change as the conditions affecting the performance of user terminals in the communication system change. The RCG 300 also provides a flexible configuration that can change as the demands change to accommodate high-throughput return link traffic in the communication system. Additionally, the RCG 400 advantageously enables the switching of return link channels on a time scale that does not cause network instability.

[0077] Figure 4AAn example of a return channel group or RCG 400 with one return link channel (id9) is shown, and the return link channel has a frequency band overlapping with two other return link channels (id8 and id10). The return link channels of RCG 400 are assigned indexes id1 to id10 to uniquely identify each return link channel. It should be noted that the index is just a way to identify the return link channel, and other ways can be adopted to identify the return link channel. For example, characteristic frequencies (such as center frequency, lower frequency, upper frequency, frequency offset) and bandwidth (such as transmission rate, frequency band width, etc.) can be used to identify the return link channel. The frequency and width of the frequency band (such as the offset from the center frequency of the frequency band and the bandwidth of the channel (for example, in Msps or Mcps or MHz)) can be used to identify or define the return link channel. For example, when allocating transmission resources or changing or updating the RCG, the identifier can be used to identify the corresponding return link channel in the RCG. For example, RCG400 includes 10 return link channels id1 to id10 with corresponding center frequencies f1 to f10. The return link channels id1 to id10 have respective transmission rates of 5Mcps (id1), 10Mcps (id2, id3), 40Mcps (id4, id5), 80Mcps (id6, id7, id8 and id9), and 160Mcps (id10).

[0078] RCG 400 is an example of an RCG that can be used in a communication system with one or more dedicated terminals, and the communication system can create sporadic demands for high-throughput return link traffic. In this example, a dedicated user terminal may be able to maintain a transmission rate of 160Mcps under nominal conditions. In response to the demand for high-throughput return link traffic, a scheduler (such as scheduler 170 or scheduler 770) can allocate the return link channel id10 to an exclusive user terminal with a transmission rate of 160Mcps. When this user terminal does not request return link bandwidth, the return link channels id8 and id9 can be allocated without potentially causing transmission burst conflicts.

[0079] To illustrate one or more advantages of RCG 400, an example is provided. Some user terminals with low transmission rates (such as 5 or 10Mcps) may not be able to operate on a return link channel with a high transmission rate (such as 160Mcps). In some communication systems with certain RCGs (such as RCGs with non-overlapping and / or sequential channelization, such as those described herein with reference to Figure 3A those), a part of the channelization is reserved for high-throughput user terminals (such as 160Mcps), such as Figure 3AThe RCG 301 in []. 3A. Then, this portion of the channelization may not be available for some low transmission rate user terminals, leaving a large portion of the available bandwidth unused when the high throughput user terminals are not transmitting. In the disclosed RCG with overlapping channelization, the high throughput return link channels can be dynamically allocated without reserving a portion of the bandwidth for the high throughput user terminals. This allows the low throughput user terminals to utilize the available bandwidth because the low throughput return link channels are also defined in the RCG with overlapping channelization (e.g., RCG 400). Then, when a high-speed user terminal requests resources for transmitting a burst, the high throughput channels can be allocated and then the low throughput channels can be used again. To recreate this ability using a non-overlapping channelization scheme, a relatively large amount of messaging is required to propagate the changes to the RCG to the user terminals of the communication system. This is undesirable, at least in part due to the latency in propagating such changes and / or the potential network instability it may cause.

[0080] The RCG 400 is configured to turn on a 160 Mcps return link channel (id10) for selected terminals as needed. When there is no demand, the return link channel utilization can revert to a regular channelization plan (e.g., a maximum transmission rate of 80 Mcps). This provides an ideal flexible configurability. Additionally, the disclosed overlapping channelization technique can be used such that the time scale of the dynamic return link channelization does not cause network instability. The disclosed overlapping channelization technique also reduces the capacity loss and fairness for non-exclusive terminals.

[0081] Figure 4B An example resource grant map 410 is shown that assigns different user terminals (labeled UT A, UT B, UT C, and UT D) to different return link channels, and these return link channels are associated with Figure 3Acorresponds to the return link channel in the RCG 400 (e.g., the RCG channel id4 in the resource grant map 410 corresponds to the channel id4 in the RCG 400). The horizontal axis represents time such that the allocation block 412 represents the corresponding transmission grant period. If there is no resource allocation, the allocation block shows "GAP". In the resource grant map 410, the RCG channel id10 is not used because channel id8 and id9 have been allocated during the period covered by the resource grant map 410, and channel id8 and id9 overlap with the channel id10 of the RCG 400. This may represent a situation where a high-capacity dedicated terminal has not requested or has not been allocated transmission resources. The resource grant map described herein is similar to the UL-MAP message used in the IEEE 802.16 standard group (e.g., Worldwide Interoperability for Microwave Access or WiMAX), which is used to allocate access to the uplink (or downlink) channel. The resource grant map described herein is simplified to illustrate certain elements of the disclosed technology, but should be understood to also include other information that is beneficial or necessary for allocating transmission resources. For example, the disclosed resource grant map may be configured to conform to the WiMAX standard set for UL-MAP. Additionally, the described resource grant map specifies a subset of channels, but should be understood to also include additional channels where appropriate.

[0082] Figure 4C Shows another example resource grant map 420 that allocates the return link channel id10 to a fifth user terminal (UT E) during a portion of the period covered by the resource grant map 420. This may represent a situation where a high-capacity dedicated terminal has requested and has been allocated transmission resources. In the resource grant map 420, the RCG channel id10 is not used during the first period because channel id8 and id9 have been allocated during the first period, and channel id8 and id9 are not used during the second period because channel id10 has been allocated during the second period.

[0083] Figure 4B and 4C Shows the performance advantages provided by the overlapping channelization technique disclosed herein. Here, the 160 Mcps channel (channel id10) is only employed when a 160 Mcps home channel is selected for a high data rate user terminal (UT E) and the user terminal has return link traffic. At all other times, the overlapping 80 Mcps channels are available for user terminals with compatible transmission rates. Because the disclosed RCG configuration allows for overlapping channelization, there is no latency in switching between different RCG configurations.

[0084] Figure 5A and 5B Shows the resource grant within a decomposed time slot ( Figure 5A) or by allocating resource grants to time slots ( Figure 5B ) Examples of resource grant mappings 510, 520 that allocate resource grants. The RCG channelization corresponds to the RCG 400 described herein. 4A. Figure 4A describes. Figure 5A shows the in-slot allocation in the resource grant mapping 510. In the resource grant mapping 510, both 80 Mcps channels and 160 Mcps channels can transmit bursts in the same time slot because the allocation is divided within the time slot. In other words, the transmission authorization period can be shorter than the time slot in the communication system and can be short enough to allocate multiple non-overlapping transmission authorization periods in the same time slot. Figure 5B shows the inter-slot allocation in the resource grant mapping 520. In the resource grant mapping 520, only two 80 Mcps channels or 160 Mcps channels can have bursts in a given time slot because the two 80 Mcps channels overlap with the 160 Mcps channels. In other words, the transmission authorization period can be approximately the same duration as the time slot in the communication system, such that the scheduler cannot allocate multiple non-overlapping transmission authorization periods in the same time slot.

[0085] Method for Allocating Transmission Resources Using Overlapped Channelization

[0086] Figure 6 shows a flowchart of an example method 600 for communicating on a communication system that supports a return channel group with overlapping channelization. Reference may be made herein Figures 1A to 2C and Figure 7 described in any scheduler in the scheduler. For ease of description, method 600 will be described as being performed by the scheduler. This should not be construed as limiting the scope of the present disclosure. Rather, any step or part of method 600 may be performed by any component or combination of components of the communication system described herein.

[0087] In block 605, the scheduler receives requests for return link bandwidth from multiple user terminals. In block 610, the scheduler allocates 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 channels are selected from a plurality of return link channels that are grouped together in a return channel group. Each return link channel covers a corresponding frequency band. The scheduler also allocates a transmission authorization period to each requesting user terminal. The plurality of return link channels in the return channel group each have different transmission characteristics, where 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.

[0088] In block 610, the scheduler determines whether the resource allocations assigned in block 605 overlap. To do this, the scheduler determines whether any frequency bands of the assigned return link channels overlap at least partially with the frequency bands of any other assigned return link channels, and whether any transmission authorization periods overlap at least partially with any other transmission authorization periods. If the scheduler determines that there are no overlapping allocations, then in block 620 the scheduler transmits the assigned return link channels and associated transmission authorization periods to the corresponding user terminals. In some embodiments, the scheduler is configured to mark the resource authorization as occupied at the time of the resource authorization assignment to avoid assigning overlapping resource authorizations to another user terminal.

[0089] If the scheduler determines that the assigned resource authorization has frequency bands and transmission authorization periods that overlap with another assigned resource authorization, then in block 625 the scheduler changes the return link channel and / or transmission authorization period of one of the overlapping allocations. The scheduler then returns to block 615 to see if there are more overlapping allocations. This loop continues until there are no more overlapping allocations.

[0090] In some embodiments, the scheduler is further configured to periodically transmit an RCG descriptor message to a plurality of user terminals, the RCG descriptor message including an update to a return channel group. The RCG descriptor message can be configured to add a return link channel to the return channel group, adjust the center frequency of a return link channel in the return channel group, adjust the bandwidth of a return link channel in the return channel group, etc.

[0091] In some embodiments, the return link channels are assigned at least in part based on the performance (e.g., bandwidth, power, etc.) of the user terminal making the request. For example, the scheduler can assign a return link channel to a user terminal where the return link channel has a bandwidth greater than or equal to the transmission rate of the corresponding user terminal. The performance of the user terminal can be affected by hardware components such as filters and amplifiers, which can affect transmission characteristics such as power and bandwidth.

[0092] In some embodiments, the channel conditions of the communication system degrade the transmission characteristics of one or more of the plurality of user terminals. In such cases, the scheduler can assign the return link channels at least in part based on the degraded transmission characteristics. The degraded transmission characteristics can include the transmission rate or duty cycle of the user terminal.

[0093] Example Scheduler

[0094] Figure 7 A block diagram of an example scheduler 770 configured to assign resource authorizations to a plurality of user terminals using a return channel group (RCG) with overlapping channelization is shown. The scheduler is similar to that described herein with reference to Figures 1A to 2CThe described scheduler 170 and can be executed in any of the communication systems described herein. The scheduler 770 can employ any of the methods described herein for allocating resource grants using an RCG with overlapping channelization, such as the example method 600 described herein with reference to Figure 6 the described example method 600.

[0095] The scheduler 770 can include hardware, software, and / or firmware components for allocating resource grants. The scheduler 770 includes a data memory 771, one or more processors 773, one or more network interfaces 775, a return link module 772, a scheduling 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 located in a virtual device residing in a public or private computing cloud. In a distributed computing environment, one or more computing devices can be configured to provide the modules 772, 774, and 776 to provide the described functionality.

[0096] The scheduler 770 includes a return link module 772 for allocating return link channels and transmission grant 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 return channel group including multiple return link channels having overlapping frequency ranges. The suitability of a return link channel can be at least partially based on the transmission characteristics of the user terminal, such as the transmission rate.

[0097] The scheduler 770 includes a scheduling conflict module 774 to analyze the allocations to determine if any of the allocations conflict with each other. A scheduling conflict can be any allocation where 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 return link channel and the second return link channel have been allocated during at least a partially overlapping period. The scheduling conflict module 774 is configured to resolve the conflict by changing one or more allocations using the return link module 772, and this process can be repeated until the determined schedule has no conflicts (e.g., overlapping allocations).

[0098] The scheduler 770 includes a forward link module 776 for allocating forward link channels and transmission grant periods to components requesting forward link bandwidth. The forward link module 776 can be configured to determine a suitable forward link channel from a channel group including multiple forward link channels having overlapping frequency ranges. The suitability of a forward link channel can be at least partially based on the transmission characteristics of the component or user terminal, such as the transmission rate.

[0099] The scheduler 770 includes one or more processors 773 configured to control the operation of modules 772, 774, 776, and data memory 771. The one or more processors 773 execute and utilize software modules, hardware components, and / or firmware elements configured to allocate resource grants using RCG with overlapping channelization. The 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. The one or more processors 773 may include other computing components configured to interface with the various modules and data storage devices of the scheduler 770.

[0100] The scheduler 770 includes data memory 771 configured to store configuration data, analysis parameters, control commands, databases, algorithms, executable instructions (e.g., instructions for the one or more processors 773), and the like. The data memory 771 may be any suitable data storage device or combination of devices, including for example but not limited to random access memory, read only memory, solid state drive, hard disk drive, flash drive, bubble memory, and the like.

[0101] Additional Embodiments and Terms

[0102] As used herein, the term "user terminal" may refer to any suitable user device capable of communicating on the disclosed communication system. Thus, a user terminal may include a user device or customer premise equipment. As used herein, resource grant, bandwidth grant, and / or reverse link grant refer to the allocation of transmission resources on a communication system, where the resources may include time slots and channels. Similarly, as used herein, resource request, bandwidth request, and reverse link request refer to a request for transmission resources on a communication system.

[0103] As used herein, the term transmission rate may be used to refer to the rate of data transmission over a network and may also be referred to as bandwidth, symbol rate, chip rate, bit rate, and the like. For example, in a direct sequence spread spectrum signal, a "chip" is an encoding element. Mcps is a measure of the speed at which a circuit can generate chips. In digital communication, a chip may refer to a pulse of a direct sequence spread spectrum (DSSS) code, such as a pseudo-random noise (PN) code sequence used in direct sequence code division multiple access (CDMA) channel access technology. In some embodiments, the chip rate and the symbol rate are the same and may be used interchangeably herein.

[0104] The present disclosure describes various features, none of which alone is responsible for the benefits described herein. It should be understood that the various features described herein may be combined, modified, or omitted, as will be apparent to those of ordinary skill in the art. Other combinations and sub-combinations in addition to those specifically described herein will be apparent to those of ordinary skill in the art and are intended to form part of the present disclosure. Various methods are described herein in connection with various flowchart steps and / or stages. It should be understood that in many cases, certain steps and / or stages may be combined such that multiple steps and / or stages shown in the flowchart may be performed as a single step and / or stage. Additionally, certain steps and / or stages may be broken into additional sub-components to be performed separately. In some cases, the order of steps and / or stages may be rearranged and certain steps and / or stages may be entirely omitted. Further, the methods described herein should be understood as open-ended such that additional steps and / or stages of those steps and / or stages shown and described herein may also be performed.

[0105] Some aspects of the systems and methods described herein may be advantageously implemented using, for example, computer software, hardware, firmware, or any combination of computer software, hardware, and firmware. The computer software may include computer-executable code stored in a computer-readable medium (e.g., a non-transitory 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. In accordance with the present disclosure, those skilled in the art will appreciate that any feature or function that can be implemented using software to be executed on a general-purpose computer can also be implemented using a different combination of hardware, software, or firmware. For example, such modules may be implemented entirely in hardware using a combination of integrated circuits. Alternatively or additionally, such a feature or function may be implemented entirely or in part using a special-purpose computer designed to perform the specific functions described herein rather than by a general-purpose computer.

[0106] Multiple distributed computing devices may replace any one of the computing devices described herein. In such distributed embodiments, the functionality of one computing device is distributed (e.g., via a network) such that some functions are performed on each of the distributed computing devices.

[0107] Some embodiments may be described with reference to equations, algorithms, and / or flowchart illustrations. These methods may be implemented using computer program instructions executable on one or more computers. These methods may also be implemented individually as a computer program product, or as components of a device or system. In this regard, each equation, algorithm, flowchart box or step, and combinations thereof, may 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 appreciated, any such computer program instructions may be loaded onto one or more computers, including but not limited to general-purpose or special-purpose computers, or other programmable processing devices for generating a machine, such that the computer program instructions executed on the computer or other programmable processing device implement the functions specified in the equation, algorithm, and / or flowchart. It should also be understood that each box in each equation, algorithm, and / or flowchart illustration, and combinations thereof, may be implemented by a special-purpose hardware-based computer system that performs the specified functions or steps, or by a combination of special-purpose hardware and computer-readable program code logic devices.

[0108] In addition, computer program instructions, such as those embodied in computer-readable program code logic, may also be stored in a computer-readable memory (e.g., a non-transitory computer-readable medium), which may direct one or more computers or other programmable processing devices to function in a particular manner, such that the instructions stored in the computer-readable memory implement the functions specified in the flowchart boxes. The computer program instructions may also be loaded onto one or more computers or other programmable computing devices to cause a series of operational steps to be executed on the one or more computers or other programmable computing devices to produce a computer-implemented process, such that the instructions executed on the computer or other programmable processing device provide the steps for implementing the functions specified in the equation, algorithm, and / or flowchart boxes.

[0109] Some or all of the methods and tasks described herein can be performed and fully automated by a computer system. In some cases, the computer system can include multiple different computers or computing devices (e.g., physical servers, workstations, storage arrays, etc.) that communicate and interoperate via a network to perform the described functions. Each such computing device typically includes a processor (or processors) that executes program instructions or modules stored in a memory or other non-transitory computer-readable storage medium or device. The various functions disclosed herein can be embodied in such program instructions, although some or all of the disclosed functions can alternatively be implemented in dedicated circuitry of the computer system (e.g., ASIC or FPGA). Where the computer system includes multiple computing devices, these devices can but need not be co-located. The results of the disclosed methods and tasks can be persistently stored by converting physical storage devices such as solid-state memory chips and / or disks into different states.

[0110] Unless the context clearly requires otherwise, throughout the specification and claims, the words "comprise", "comprising", and the like shall be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is, "including but not limited to". As generally used herein, the word "coupled" refers to two or more elements that can be directly connected or connected by means of one or more intermediate elements. Additionally, when used in this application, the words "herein", "above", "below", and words of similar import shall refer to the application as a whole and not to any particular part of the application. Where context permits, the singular or plural words used in the above detailed description may also respectively include the plural or singular. For the word "or" in a list of two or more items, the word covers all of the following interpretations of the word: any item in the list, all items in the list, and any combination of items in the list. The word "exemplary" is used herein exclusively to mean "serving as an example, instance, or illustration". Any particular embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0111] The present disclosure is not intended to be limited to the specific embodiments shown herein. Those skilled in the art can readily understand various modifications to the embodiments described in the present disclosure, and the general principles defined herein can be applied to other embodiments without departing from the spirit or scope of the present disclosure. The teachings of the present disclosure provided herein can be applied to other methods and systems and are not limited to the above-described methods and systems, and the elements and actions of the various embodiments described above can be combined to provide additional embodiments. Therefore, the novel methods and systems described herein can be embodied in various other forms; in addition, various omissions, substitutions, and changes can be made to the forms of the methods and systems described herein without departing from the spirit of the present disclosure. The appended claims and their equivalents are intended to cover such forms or modifications that fall within the scope and spirit of the present disclosure.

Claims

1. A method for communication in a communication system, the method comprises: receiving requests for return link bandwidth from a first user terminal and from a second user terminal; allocating a first return link channel to the first user terminal at least in part based on transmission characteristics of the first user terminal, the first return link channel being selected from a plurality of return link channels grouped together in a return channel group, the first return link channel including a first frequency band; allocating a first transmission authorization period to the first user terminal; allocating a second return link channel to the second user terminal at least in part based on transmission characteristics of the second user terminal, the second return link channel being selected from the plurality of return link channels in the return channel group, the second return link channel including a second frequency band; allocating a second transmission authorization period to the second user terminal; and transmitting the first return link channel, the first transmission authorization period, the second return link channel, and the second transmission authorization period to corresponding user terminals, wherein the plurality of return link channels in the return channel group each have different transmission characteristics, and wherein at least one return link channel has a frequency band that at least partially overlaps with a frequency band of another return link channel.

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

3. The method according to any one of claims 1 or 2, further comprises: determining whether the first frequency band at least partially overlaps with the second frequency band; and determining whether the first transmission authorization period at least partially overlaps with the second transmission authorization period.

4. The method according to claim 3, further comprising, in response to determining that the first frequency band at least partially overlaps with the second frequency band and the first transmission authorization period at least partially overlaps with the second transmission authorization period, allocating 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.

5. The method according to any one of claims 3 or 4, further comprising, in response to determining that the first frequency band at least partially overlaps with the second frequency band and the first transmission authorization period at least partially overlaps with the second transmission authorization period, allocating a third transmission authorization period to the first user terminal, wherein the third transmission authorization period does not overlap with the second transmission authorization period.

6. The method according to any one of claims 3 or 4, wherein transmitting the allocated return link channel and transmission authorization period to the first user terminal and the second user terminal is in response to determining that the first frequency band does not overlap with the second frequency band or the first transmission authorization period does not overlap with the second transmission authorization period.

7. The method according to any one of claims 1 to 6, wherein the return channel group is hard-coded in the first user terminal and the second user terminal.

8. The method according to any one of claims 1 to 7, wherein all possible return link channels of the communication system are included in the return channel group.

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

10. The method according to any one of claims 1 to 9, wherein each return link channel in the return channel group has a common lower frequency limit.

11. The method according to any one of claims 1 to 10, further comprising periodically transmitting a return channel group descriptor message to the first user terminal and to the second user terminal, the return channel group descriptor message including an update to the return channel group.

12. The method according to claim 11, 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 channels in the return channel group, or adjusts the bandwidth of the return link channels in the return channel group.

13. The method according to any one of claims 1 to 11, wherein 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.

14. The method according to any one of claims 1 to 13, wherein the channel conditions of the communication system deteriorate the transmission characteristics of the first user terminal, and the first return link channel is assigned to the first user terminal at least partially based on the deteriorated transmission characteristics.

15. A communication system for providing communication over a network, the system comprising: a first user terminal having a first maximum bandwidth, the first user terminal being 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 being configured to store the return channel group; and a gateway configured to communicate with the first user terminal and the second user terminal over the network, the gateway including a scheduler configured to: store the return channel group; assign a first return link channel from the return channel group to the first user terminal at least partially based on the first maximum bandwidth, the first return link channel including a first frequency band; assign a first transmission authorization period to the first user terminal; assign a second return link channel from the return channel group to the second user terminal at least partially based on the second maximum bandwidth, the second return link channel including a second frequency band; assign a second transmission authorization period to the second user terminal; and transmit the first return link channel, the first transmission authorization period, the second return link channel, and the second transmission authorization period to the corresponding user terminals. wherein each of the plurality of return link channels in the return channel group has different transmission characteristics, and wherein at least one return link channel has a frequency band that at least partially overlaps with the frequency band of another return link channel.

16. The communication system according to claim 15, wherein the network comprises a satellite network having at least one satellite in a near-earth orbit.

17. The communication system according to any one of claims 15 or 16, wherein the network comprises a satellite network having at least one satellite in a medium-earth orbit.

18. The communication system according to any one of claims 15 to 17, wherein the network comprises a satellite network having at least one geostationary earth orbit satellite.

19. The communication system according to any one of claims 15 to 18, wherein the network comprises a terrestrial network.

20. The communication system according to any one of claims 15 to 19, wherein the network comprises a cellular network.

21. The communication system according to any one of claims 15 to 20, wherein the first maximum bandwidth is different from the second maximum bandwidth.

22. The communication system according to any one of claims 15 to 21, wherein the duty cycle of the first user terminal is different from the duty cycle of the second user terminal.

23. The communication system according to any one of claims 15 to 22, wherein the first return link channel is allocated at least in part based on channel conditions that reduce the duty cycle of the first user terminal.

24. The communication system according to any one of claims 15 to 23, wherein the first return link channel is allocated at least in part based on channel conditions that reduce the first maximum bandwidth.

25. A scheduler in a communication system, the scheduler comprising: a network interface configured to communicate with a first user terminal and a second user terminal via the communication system; a data memory configured to store computer-executable instructions for generating a return link schedule that allocates a return link bandwidth to a user terminal in response to a request for a return link bandwidth from the user terminal, and to store a return channel group comprising a plurality of return link channels; and a processor configured to execute the computer-executable instructions to: allocate a first return link channel from the return channel group to the first user terminal, the first return link channel comprising a first frequency band; allocate a first transmission authorization period to the first user terminal; allocate a second return link channel from the return channel group to the second user terminal, the second return link channel comprising a second frequency band; allocate a second transmission authorization period to the second user terminal; and transmit the first return link channel, the first transmission authorization period, the second return link channel, the second transmission authorization period to the corresponding user terminal, wherein each of the plurality of return link channels in the return channel group has different transmission characteristics, and wherein at least one return link channel has a frequency band that at least partially overlaps with the frequency band of another return link channel.

26. The scheduler according to claim 25, wherein the processor is further configured to perform the following: Determine whether the first frequency band at least partially overlaps with the second frequency band; and Determine whether the first transmission authorization period at least partially overlaps with the second transmission authorization period.

27. The scheduler according to claim 26, wherein in response to determining that the first frequency band at least partially overlaps with the second frequency band and the first transmission authorization period at least partially overlaps with the second transmission authorization period, the processor is further configured to allocate 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.

28. The scheduler according to any one of claims 26 or 27, wherein in response to determining that the first frequency band at least partially overlaps with the second frequency band and the first transmission authorization period at least partially overlaps with the second transmission authorization period, the processor is further configured to allocate a third transmission authorization period to the first user terminal, wherein the third transmission authorization period does not overlap with the second transmission authorization period.

29. The scheduler according to any one of claims 26 to 28, wherein the processor is configured to transmit the allocated return link channel and transmission authorization period to the first user terminal and the second user terminal in response to determining that the first frequency band does not overlap with the second frequency band or the first transmission authorization period does not overlap with the second transmission authorization period.

30. The scheduler according to any one of claims 25 to 29, wherein all possible return link channels of the communication system are included in the return channel group.

31. The scheduler according to any one of claims 25 to 30, wherein the processor is further configured to periodically transmit a return channel group descriptor message to the first user terminal and to the second user terminal, the return channel group descriptor message including an update to the return channel group.

32. The scheduler according to claim 31, 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 channels in the return channel group, or adjusts the bandwidth of the return link channels in the return channel group.

33. The scheduler according to any one of claims 25 to 32, wherein the return channel group is a first return channel group, and wherein the processor is further configured to allocate a first return link channel from a second return channel group to a third user terminal, the second return channel group having a different channelization scheme compared to the first return channel group.

34. The scheduler according to claim 33, 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.

35. The scheduler according to any one of claims 33 or 34, wherein the processor is further configured to allocate one or more of the plurality of return link channels from the first return channel group to a user terminal communicating via a first beam in the communication system, and allocate one or more of the plurality of return link channels from the second return channel group to a user terminal communicating via a second beam in the communication system.

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