Cross-layer design for closed loop feedback in wireless networks

Abstract

The present application relates to cross-layer design for closed loop feedback in wireless networks, and discloses a system and method for communicating data. The system includes a plurality of modems for receiving uplink data and transmitting downlink data, a switch communicatively coupled to the plurality of modems, the switch including a plurality of data queues, the switch for switchably accepting uplink data from the plurality of modems and switchably providing downlink data from the plurality of data queues to the plurality of modems, and a controller communicatively coupled to the plurality of modems and the switch, the controller for providing controller information for dynamically controlling the switch to switchably accept uplink data from the plurality of modems and switchably provide downlink data from the plurality of data queues to one or more of the plurality of modems on a per terminal and per communication link basis.

Description

Technical Field

[0001] The present disclosure relates to systems and methods for communicating information, and in particular to systems and methods for dynamically allocating communication resources. Background Art

[0002] Satellite architectures for transmitting information from one terminal to another are known. Typically, a satellite in this architecture consists of a switch or router and a communicatively coupled modulator / demodulator (MODEM) or collection of MODEMs. The switch acts as an aggregation device, connecting MODEM uplink information from one terminal to MODEM downlink information destined for one or more other terminals. The switch determines where to deliver received packets and frames and provides those packets and frames to the MODEM designated to transmit the information to the receiving terminal. The MODEM receives / transmits RF energy (on the terminal side) and converts the RF information into digital frames of data (on the switch side). The switch has a large buffer for buffering frames during processing. Conversely, the MODEM contains a small buffer (e.g., a ping-pong frame buffer) for buffering frames during MODEM processing. The MODEM buffer has a finite size and can overflow if more uplink frames are delivered to the buffer from the switch's egress queue than downlink frames are removed from the MODEM buffer for downlink to the receiving terminal. When the buffer overflows, there is a risk of frame and other data being lost and unrecoverable. Furthermore, the terminal data rate can vary significantly over time. This variation in the terminal data rate increases the risk of buffer overflow.

[0003] Some terminals are mobile. Another problem arises when a terminal receiving data moves from an area or downlink forwarding access (DFA) served by a satellite beam and channel combination (hereinafter referred to as a beam-channel group) to another DFA served by a different satellite beam and / or channel. In these cases, the system causes the DFA to follow the terminal to the new location (for example, by manipulating the satellite beam) or reconnects the terminal to the satellite at the new DFA. Having the DFA follow the terminal is difficult to implement for a large number of terminals, and reconnecting the terminal to the satellite at the new DFA often results in packet loss. Summary of the Invention

[0004] This summary is provided to introduce some concepts in a simplified form that are further described in the detailed description below. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0005] To address the aforementioned needs, this document discloses a system and method for transmitting data. An example is described by a system for transmitting data from multiple communication terminals, the multiple communication terminals including a first communication terminal served by a first communication link and a second communication terminal served by a second communication link, the first communication link having a beam and channel combination serving a first area, and the second communication link having a second beam and channel combination serving a second area. The system includes: a plurality of modems for receiving uplink data and transmitting downlink data; a switch communicatively coupled to the plurality of modems, the switch including a plurality of data queues, the switch for switchably accepting uplink data from the plurality of modems and switchably providing downlink data from the plurality of data queues to the plurality of modems; and a controller communicatively coupled to the plurality of modems and the switch, the controller for providing controller information for dynamically controlling the switch to switchably accept uplink data from the plurality of modems and switchably provide downlink data from the plurality of data queues to one or more of the plurality of modems on a per-terminal and per-communication link basis.

[0006] Another embodiment is demonstrated by a method for transitioning a communication terminal from a first communication link to a second communication link, the method being implemented, for example, in a system for transmitting data from a first communication terminal to a second communication terminal, the system comprising: a plurality of modems for receiving uplink data and transmitting downlink data; a switch communicatively coupled to the modems, the switch including a plurality of data queues, the switch for switchably accepting uplink data from the plurality of modems and switchably providing downlink data to the plurality of modems; and a controller communicatively coupled to the modems and the switch, the controller for controlling the switch to switchably accept uplink data from the plurality of modems and switchably provide downlink data from the data queues to the plurality of modems. The method comprises: determining that the communication terminal is predicted to leave a first area served by the first communication link and enter a second area served by the second communication link; and dynamically and losslessly relinking the plurality of data queues associated with the communication terminal from the first communication link to the second communication link. Another example is described by dynamically and losslessly relinking all of a plurality of data queues associated with a communication terminal from a first communication link to a second communication link, the relinking comprising: receiving queue occupancy data describing occupancy of the data queues; determining, based on the queue occupancy data and a predicted area served by the second communication link, to relink all of the plurality of data queues associated with the communication terminal from the first communication link to the second communication link; and relinking a first group of the plurality of data queues from a first group of one or more of a plurality of modems to a second group of one or more of the plurality of modems.

[0007] The features, functions, and advantages that have been discussed can be achieved independently in various embodiments of the present invention or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Referring now to the drawings, wherein like reference numerals designate corresponding parts throughout:

[0009] Figure 1 is a diagram illustrating one embodiment of a communication system;

[0010] Figure 2A and Figure 2B It is a diagram of a switch, a modem, and a controller;

[0011] Figure 3 is a diagram illustrating one embodiment of an exemplary system for communicating data;

[0012] Figure 4is a diagram illustrating an exemplary process for transmitting data for transitioning a terminal from a first communication link to a second communication link;

[0013] Figure 5 is a diagram illustrating an exemplary process for dynamically and losslessly relinking all of a plurality of data queues associated with a communication terminal from a first communication link to a second communication link;

[0014] Figure 6 An exemplary computer or processing system 600 including a switch, a MODEM, and a controller that may be used to implement the processing elements disclosed above is shown. DETAILED DESCRIPTION

[0015] In the following description, reference is made to the accompanying drawings, which form a part hereof, and several embodiments are shown by way of illustration. It should be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present disclosure. To the extent that the terms "include," "comprising," "having," "containing," and variations thereof are used herein, such terms are intended to be inclusive as open transition words in a manner similar to the term "comprising," without excluding any additional or other elements.

[0016] Overview

[0017] The integration of physical layer (Layer 1) functionality in a modem and media access control layer (Layer 2) functionality in an L2 switch provides a system that is more responsive to changes in the load or environmental conditions in which the system is operating. The present invention describes multiple cross-layer design strategies for effectively coupling a modem with demand-assigned multiple access (DAMA) and adaptive coding and modulation (ACM) capabilities, a QoS-aware L2 switch, associated modem and switch controller functionality, and adaptive coding and modulation / demand-assigned multiple access (ACM / DAMA) algorithms, such as dynamic resource allocation (DRA). Finally, a dynamic queue relinking function is provided that allows a set of per-service-category / per-terminal queues to be dynamically relinked from one downlink carrier to another, thereby providing seamless (i.e., all terminal applications persist throughout the entire mobility event) mobility performance for dynamic resource allocation and terminal mobility scenarios. In scenarios where terminals support simultaneous multi-beam attachment, dynamic queue relinking uses a make-before-break handover strategy, supporting lossless mobility performance for DRA and terminal mobility scenarios.

[0018] This addresses the logical coupling between: the ever-changing user terminal data rates managed by a dynamic resource allocation algorithm (associated with the DMA function in the MODEM), the adaptive coding and modulation function in the MODEM that dynamically changes the modulation and coding used on the variable-quality RF link, the token bucket size and leakage rate of the ingress traffic policing function on the Layer 2 switch, the egress scheduling weights on the weighted fair queuing scheduler on the ingress (downlink) of the Layer 2 switch, the dynamic mapping of per-terminal / per-class of service (CoS) queues to DFA queues, and the physical coupling of the egress queues on the Layer 2 switch with the frame buffers on the MODEM that allow the MODEM to apply back pressure to the Layer 2 switch at the beginning of a transient congestion period.

[0019] In addition to the handling of unicast traffic described above, a set of per-CoS multicast queues is provided on the egress side of the switch to provide QoS-aware forwarding of multicast frames to the DFA containing endpoints that are members of a given multicast group. The switch maintains a multicast group membership list by listening to multicast group management traffic traversing the network control plane.

[0020] System Architecture

[0021] Figure 1 1 is a diagram illustrating one embodiment of a communication system 10 for transmitting information from a first terminal 104A to a second terminal 104B. The first terminal 104A or the second terminal 104B may include a mobile terminal 104M. The terminal 104 is a collection of equipment typically located on the ground, including a modem 114, switches and routers (to collect and disseminate data from multiple sources within the terminal), as well as telephones, computers, and other devices.

[0022] The communication system includes an airborne or space vehicle, such as a satellite 102, that receives uplink data from a first terminal 104A via a first communication link 110A and transmits the uplink data to a second terminal 104B via a second communication link 110B.

[0023] As described herein, communication link 110 is defined as a communication channel implemented using a combination of beam 106 (e.g., RF beam) and a channel of information carried on the RF beam 106. For example, communication link 110A is implemented by beam 106A and one or more channels of information transmitted on those channels. As described herein, "channels" may include channels distinguished from one another via any multiple access paradigm, including frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), or any combination thereof. Each communication link 110A-110N serves a corresponding region 108A-108N. In embodiments where satellite 102 is in geosynchronous or geostationary orbit (GEO), the geographic region 108 served by satellite 102 does not move over time, but rather remains stationary. In other embodiments (satellites 102 in orbits other than GEO, such as medium Earth orbit (MEO) or low Earth orbit (LEO), or aerial vehicles), region 108 may change over time as satellite 102 moves. The communication link 110 will also be referred to interchangeably hereinafter as a downlink forwarding access area or (DFA) 100 .

[0024] As described above, the terminals 104 may be stationary or may be mobile (represented by 104M), and thus, the mobile terminal 104M may move from an area 108B to another area 108N, as indicated by the mobile terminal 104M'.

[0025] The satellite 102 includes one or more switches 112 communicatively coupled to one or more modems 114. As described herein, the modems 114 include, for example, "software defined radios (SDRs)" that allow the modems to instantiate various waveforms (e.g., 2G / 3G / 4G / 5G cellular, MF-TDMA VSAT waveforms, spread spectrum DoD waveforms, etc.) via software upload or firmware configuration. The functions of the modems 114 are to accept RF signals uplinked from the terminals 104 (Layer 1), generate data frames (Layer 2) from those RF signals and provide them to the switches 112 for transmission to the same or other modems, and to accept data frames from the switches 112, generate RF signals from those frames, and downlink those signals to one or more of the terminals 104. Switch 112 is an aggregation device that communicatively couples to the MODEMs and determines which MODEMs 114 to accept packets or frames from, determines which MODEMs 114 the received packets and frames should be routed to, and routes those packets and frames to those MODEMs.

[0026] Switch 112 and modem 114 communicate via an interface such as SERDES. SERDES (serializer / deserializer) is a pair of functional blocks (serializer and deserializer) commonly used in high-speed (3.125-112 Gb / s) communications. These blocks convert data between a serial data interface and a parallel data interface in each direction. The SERDES standard, IEEE 802.3, has been adopted and is incorporated herein by reference.

[0027] Dedicated data queue

[0028] Figure 2A and Figure 2B is a diagram of the switch 112, the MODEM 114, and the controller 254. The controller 254 controls the switch and the MODEM 114 to implement dynamic resource allocation (DRA), and is hereinafter also referred to alternatively as a MODEM controller or a DRA controller.

[0029] Each MODEM 114 includes MODEM data queues, including a priority data queue 270P for priority data and a weighted queue 270W for other data. Each MODEM also includes a buffer 268 that buffers data entering and leaving the MODEM 114.

[0030] The switch 112 is communicatively coupled to a plurality of modems 114. The switch 112 includes a plurality of data queues 204, and the switch 112 can switchably receive uplink data from the modems 114 and can switchably provide downlink data from the plurality of data queues 204 to the plurality of modems 114. A modem controller 254, communicatively coupled to the plurality of modems 114 and the switch 112, provides controller information for dynamically controlling the switch 112 to switchably receive uplink data from the plurality of modems 114 and switchably provide downlink data from the plurality of data queues 204 to one or more of the plurality of modems 114 on a per-terminal 104 and per-communication link 110 basis. In one embodiment, the controller information is determined at least in part based on the occupancy (data enrichment) of the data queues 204.

[0031] The switch 112 includes a plurality of data queues 204, a per-terminal scheduler 206, a per-DFA scheduler 208, an ingress traffic policing module 210, a queue occupancy statistics module 212, and a data queue scheduling and weight configuration module 214. The switch data queues 204 include queues for unicast frames 204U and multicast frames 204M. Different queues 204 are provided for data associated with different Class of Service (CoS) requirements (and therefore different priorities), which can be defined, for example, by the Metro Ethernet Forum (MEF) to include high quality of service (QoS) 204UH1-204UHN and 204MH1, medium quality of service (QoS) 204UM1-204UMN and 204MM1, low quality of service (QoS) 204UL1-204ULN and 204ML1, and best effort quality of service (BEST) 204UB1-204UBN and 204MB1.

[0032] Each terminal 104 has its own set of CoS queues 204. Thus, for example, queues 204UH1, 204UM1, 204UL1, and 204UB1 can all be dedicated to a particular terminal 104. All communication traffic for that terminal 104 is handled by a set of queues 204 that are not shared with other terminals, and the occupancy of the multiple data queues is determined on a per-terminal basis and a per-DFA basis.

[0033] This design has several advantages. The granularity of the queues allows a set of queues to be dynamically relinked from one DFA (e.g., communication link 110) to another DFA without data loss. A DFA 110 is a combination of beams and channels used by a satellite 102 to communicate with a terminal 104. A terminal 104 can migrate from the DFA 110 currently being used to communicate with the satellite (the resident DFA 110) to another DFA 110 (the target DFA 110) due to a change in channel assignments, a change in the RF beam 106 used for communication between the terminal 104 and the satellite, or both.

[0034] A change in DFA 110 due to a change in the RF beams 106 used to communicate with satellite 102 is referred to as a mobility event. Since DFA 110 is defined by a combination of beams 106 and the channels of data being transmitted on those beams 106, and since those beams 106 generally serve corresponding geographic areas 108 that do not move over time, a mobility event occurs whenever a terminal transitions from one geographic area 108B to another geographic area 108N.

[0035] This is similar to what happens when a cell phone moves from one communication tower or sector to another. However, when this handoff occurs in a cell phone system, the radio frequency (RF) connection between the cell phone and the tower is maintained, but because data buffers are not transferred between towers, the handoff is typically completed at the expense of some packet loss. This can cause the video data being reproduced on the cell phone to freeze (e.g., due to the loss of an I-frame or another frame of the video).

[0036] In contrast to the aforementioned handset handoff, the disclosed system dedicates a set of queues to a specific terminal 104. This allows for lossless handoff because the set of data queues 204 and all data within those queues 204 are dynamically remapped from the resident DFA 110 to the target DFA 110, thus avoiding packet loss. The dynamic remapping of data queues 204 is implemented by a remapping module comprising a per-terminal scheduler 206 and a per-DFA scheduler 208, which update the mappings in the switch 112 and provide the updated mappings with changes to the DFA 110 to the modem 114. In embodiments with frequency hopping or similar schemes, frequency hopping mappings can also be provided. Since the modem 114 receives data frames or packets from a specific mapping in the DFA 110 on the switch 112, the changes are transparent from the modem's perspective. In one embodiment, the handoff is synchronized by the switch 112 so that it occurs on a single clock edge, resulting in no data frame loss. This technique may also be referred to as dynamic queue relinking.

[0037] This dynamic queue relinking is accomplished during a mobility event when the terminal 104 transitions an epoch boundary, which is a time boundary 110. Determining that a terminal has or will experience a mobility event and move from a resident DFA 110 to a target DFA 110 may be determined in different ways.

[0038] In one embodiment, mobility events are determined using geographic status data (eg, position, velocity, and / or acceleration) obtained at the terminal from a positioning unit (such as a Global Positioning System or GPS receiver).

[0039] In another embodiment, a mobility event trigger is determined using RF data from the terminal 104. Typically, the antenna on the satellite 102 used to receive and transmit data to the terminal 104 has a sensitivity pattern that provides maximum gain at the center of the beam 106 and reduced gain at the periphery of the beam 106. Therefore, as the terminal 104 approaches the epoch boundary between the resident DFA 110B and the target DFA 110N, the power of the RF signal received from the terminal 104 decreases. When this power decreases below a certain threshold, it can be determined that the terminal has crossed the epoch boundary and transitioned to the target DFA 110N. The satellite 102 can determine which neighboring DFA 110 is the target DFA 110N by determining whether the RF signal from the same terminal 104 is received via an antenna serving another geographic area 108.

[0040] In another embodiment, a mobility event is triggered by the DRA controller 254 when an algorithm determines that a configured beam channel grouping (i.e., a resident DFA) is to be changed to a differently configured beam channel grouping (i.e., a target DFA). In this embodiment, these beam channel groups (DFAs) may overlap with each other in whole or in part geographically.

[0041] In yet another embodiment, a mobility event trigger may be determined by a system operator who knows the mission profile (expected location) of terminal 104 using one or both of the measurements from the other location sources described above. Any of the aforementioned techniques for determining epoch boundary transitions may be used in conjunction with other techniques to increase the accuracy of the determination or to increase system robustness.

[0042] Assignment of dedicated data queues to modems

[0043] The controller information includes per-terminal data queue scheduling information and per-DFA scheduling information and is generated and provided by controller 254, which includes downlink controller 262, uplink controller 260, and MODEM configuration manager 258. Controller 254 is hereinafter alternatively referred to as dynamic resource allocation controller or DRA controller 262.

[0044] The DRA controller 262 uses real-time occupancy statistics obtained from the queue occupancy statistics module 212 of the switch 112 to determine how much bandwidth the terminal 104 needs at a certain point in time or during a defined time period, as determined by the occupancy (data enrichment) of each CoS queue in the switch 112. The DRA controller 254 notifies the modems 114 and the switch 112 how much throughput to allocate to each modem 114 in the next DRA period. For example, if the current period is N, controller information can be generated for periods N+1 and / or N+2. A typical period can be 640 milliseconds.

[0045] Per-terminal scheduling information is generated by the downlink controller 262 based at least in part on the occupancy (data enrichment) of multiple data queues 204 on a per-terminal basis (e.g., for the terminal 104) as provided by the queue occupancy statistics module 212 and data requests received by the satellite 102 via the uplink controller 260.

[0046] Per-DFA scheduling information is also generated by downlink controller 262 based at least in part on the occupancy (data enrichment) of the plurality of data queues 204 on a per-DFA basis as provided by queue occupancy statistics module 212 and data requests received by satellite 102 via uplink controller 260. The controller information is provided to queue scheduling and weight configuration module 214 and is used to schedule data queues 204 using per-terminal scheduler 206 and per-DFA scheduler 208.

[0047] The per-terminal scheduler 206 schedules the provision of data in the data queues 204 to the associated terminals 104 on a per-terminal basis according to the per-terminal scheduling information, and switchably provides the data in the data queues 204 to the associated terminals 104. For example, the frames in the data queue 204UH1 include frames to be delivered with a high CoS, and the per-terminal scheduler 206 provides the data in this data queue 2014UH1 to the per-DFA scheduler 208 (described further below) at a higher priority than the remaining data queues 204UM1, 204UL1, and 204UB1 for the terminal 104, for ultimate provision to one or more of the modems 114.

[0048] Similarly, data in data queues 204UM1, 204UL1, and 204UB1 is provided to DFA scheduler 208 on a weighted fair queuing basis (WFQ) as determined by queue scheduling and weight configuration module 214 for ultimate provision to MODEM 114 and the terminals. Queue scheduling and weight configuration module 214 informs the per-terminal 206 scheduler and per-DFA scheduler 208 of the relative allocation of resources to provide to each queue priority level. In one embodiment, a hierarchical queue structure is assumed with a total weight of all data types equal to 1 (one) and a percentage of the total weight allocated to each data type. For example, a high priority data type may be assigned a weight of 0.5, and a low priority data type may be assigned a weight of 0.1, leaving the remaining data types assigned the remaining weight of 0.4.

[0049] The per-DFA scheduler 208 can switchably provide per-terminal scheduled downlink data from the plurality of queues 204 on a per-DFA basis according to the per-DFA scheduling information. For example, the data frames in the data queues 204UH1, 204UM1, 204UL1, and 204UB1, once scheduled with each other for a specific terminal 104, are further rescheduled on a per-DFA basis to be provided to a specific DFA 110 (e.g., a MODEM supporting that DFA 110).

[0050] In one embodiment, the controller 254 includes an uplink controller 260 that provides modem configuration data to the modem 114 to configure it for downlink data transmission. This configuration data includes DFA 110 changes (e.g., whether a modem that was previously assigned to a particular DFA 110 is reassigned to a different DFA 110). This data may include, for example, terminal communication link mappings for dynamically remapping per-terminal and / or per-CoS service queues from a parked DFA 110 to a target DFA 110. In one embodiment, the uplink controller 260 also provides ingress traffic policing information to the ingress traffic policing information module 210 of the switch 112. This ingress traffic policing information is Layer 1 communication information and may include a per-terminal token bucket filter that meters and marks data traffic to determine whether each set of data complies or does not comply with the service local protocol associated with the associated terminal 104. If the data complies, it is marked as passing data traffic on a Layer 1 basis. If the data is partially compliant (e.g., the requested data rate is somewhat between the average throughput and the peak throughput), the data is marked as a candidate to be discarded rather than transmitted. If the data is not compliant (e.g., above the peak rate that can be provided), the data can be discarded a priori. Ingress traffic policing information provides a way to ensure that the terminal 104 is adhering to its service level agreement. This ingress traffic policing information can include the terminal data rate and burst size and can be filtered by the EWMA filter 266.

[0051] The uplink controller 260 also implements a demand-assigned multiple access (DAMA) communication paradigm that allows the DRA controller 262 to communicate with the terminals 104 to accept data requests. For example, a terminal may transmit information indicating that at time period N+2, the terminal 104 will require a specific throughput. The DRA controller 262 accepts requests from all terminals 104 served by the satellite 102 and arbitrates between them based on queuing priorities and communication resources, optimizing the allocation among all terminals.

[0052] The DRA controller 262 may also include statistical multiplexing capabilities and an adaptive coding and modulation (ACM) controller. This allows the MODEM 114 to change the modulation and coding parameters used by the MODEM to adapt to the conditions present in the communication link 110. Such conditions may be provided by an external source (such as, for example, a weather information source) or by an internal source (such as a signal strength measurement tool and the MODEM itself). For example, under clear sky conditions (which may be provided by an external weather information source), error correction may be almost unnecessary, and a modulation and coding scheme that maximizes throughput but is not robust enough may be selected. If the weather is not clear, a more robust coding and / or modulation scheme may be employed that provides greater error correction capability or error resistance. In this way, the downlink controller may provide the MODEM 114 with information about what MODEM parameters to use during which period. Since satellites 102 are typically bent pipes (accepting uplink information from one terminal 104 and downlinking that information to one or more other terminals 104), the fact that a data request from a terminal 104 requires high throughput can be used to determine that at a later time, another MODEM will need to retransmit that data to another terminal 104. Generation of this information can be performed by the MODEM configuration manager 258.

[0053] The DRA controller 262 may also include a low-pass filter 264 for filtering the queue occupancy statistics provided by the queue occupancy statistics module 212. Filtering out high-frequency variations in the queue occupancy data is important because short-term changes in response to queue occupancy can cause system instability. High-frequency variations represent a form of noise to the system, and filtering out these factors allows the DRA controller to focus on the slow-moving statistics of the signal. In one embodiment, the filter 264 includes an exponentially weighted moving average filter (EWMA).

[0054] In one embodiment, switch 112 also controls each of the plurality of modems 114 to delay sending uplink data to switch 112 in the event that data queue 204 overflows. Typically, this delay is only a matter of one or two frames, so switch 112 can clear data queue 204 before accepting new data. This can be implemented using a direct physical layer (Layer 1), thereby allowing for very fast responses from modem 114. For example, data and command exchanges between switch 112 and modem 114 are performed via a high-speed, bidirectional interconnect, such as a serial / deserialization (SERDES) interface. This interface can be optical and allows switch 112 to communicate directly with modem 114 without using a DRA controller 262. Unlike DRA controller 262, which controls modem 114 and its interface with switch 112 at higher layers, such as Layer 2 (data link), Layer 3 (network), or Layer 4 (transport), the use of a high-speed, bidirectional Layer 1 interface allows for faster responses. Thus, control of elements of the communication system 100 is performed simultaneously across layers using both Layer 1 and higher layers.

[0055] In one embodiment, switch 112 communicates with modem 114 via the SERDES interface using one bit of the SERDES frame header to indicate a transmit off (XOFF=0) or transmit on (XON=1) command to instruct modem 114 to stop sending data or resume sending data, respectively.

[0056] Exemplary embodiments

[0057] Figure 3 is a diagram illustrating one embodiment of an exemplary process for transmitting data. The steps discussed below are Figure 3 The circled numbers depicted in FIG. 30 indicate that demodulator 302 and modulator 308 represent the physical layer elements of modem 114. Additionally, some MAC / LLC layer MODEM 114 functions are hosted by system controller 254.

[0058] In step 1, the user terminal or gateway terminal 104 creates a backbone port (BP) encapsulation and forwards the provider backbone bridge network (PBBN) Ethernet frame to the satellite payload. In step 2, the demodulator 302 of the MODEM 114 receives the I&Q from the integrated phased array (IPA), demodulates and decodes the signal, reconstructs the BP-encapsulated PBBN Ethernet frame, adds an internal shim header (containing the terminal 104 identifier or ID), and forwards the resulting frame through the SERDES to the backbone core bridge (BCB) via the GbE switch of the BCB 304.

[0059] In step 3, the ingress Gigabit Ethernet physical layer (GbE PHY) 310 performs SERDES transceiver functions, SERDES framing, byte synchronization / detection, descrambling, 8b / 10b decoding, and 10 / 100 / 1000 auto-negotiation.

[0060] In step 4, the ingress GbE media access control layer (MAC) 324 verifies the frame format, frame length, and frame check sequence (FCS, similar to a checksum) of the incoming frame and updates the associated Simple Network Management Protocol (SNMP) Management Information Base (MIB) counters. The MIB is a definition of management objects within the modulator 308 and demodulator 302 using SNMP. SNMP is used to obtain counter values ​​from the data queue 204 to generate queue occupancy statistics that are provided to the controller 254.

[0061] In step 5, the ingress classifier 314 of the controller 254 parses the arriving frame based on a predefined N-tuple (e.g., terminal ID), a trunk destination address (B-DA), a trunk source address (B-SA), a trunk tag (B-TAG) priority code point (PCP) that uses a set of bits (e.g., 3 bits) to provide a value from zero to seven to indicate the priority of the received data, a B-TAG discard eligibility indicator (DEI) indicating that the frame can be discarded if necessary, and a B-TAG video identifier (VID), and places the frame in external memory and creates frame metadata for processing the frame according to steps 6 and 7.

[0062] In step 6, the classified frames (metadata) are checked against the configured filtering policies (e.g., access control lists or ACL entries) and are metered and marked according to the ingress traffic policing function (implemented as a token bucket filter). This is performed by the ingress filter processor 315 of the uplink controller 260.

[0063] In step 7, the BP-encapsulated PBBN Ethernet frame (metadata) is forwarded through the switch 112 fabric, where the appropriate egress switch port is selected based on the contents of the associated row entry in the forwarding information base (FIB) 318, which is similar to a switch table. The contents of the FIB 318 are managed by the controller 254 and determine which data queues 204 are provided and switched to which modems 114.

[0064] In step 8, upon switching to the egress side, the egress queuing and discarding module 320 of the switch 112 checks the PBBN Ethernet frame (metadata) for discard eligibility (asserted B-TAG DEI) and either discards (when the switch 112 is operating in a congested area) or queues it into a per-CoS / per-endpoint egress queue 204 mapped to a unique DFA 110 by the DRA controller 262. This hierarchical egress queuing employs priority queuing for delay-sensitive traffic and weighted fair queuing for all other types of traffic.

[0065] In step 9, the egress priority fair scheduler 322 of switch 112 schedules the PBBN Ethernet frame (metadata) for transmission. Prior to transmission, the PBBN Ethernet frame is reconstructed using the metadata and the frame content stored in external memory. The per-DFA XON / XOFF backpressure mechanism represents a level 1 feedback loop 326 that allows a modem to provide information to switch 112 (via XON or XOFF) indicating that the modem's queue or buffer is full, and temporarily pauses switch 112's DFA scheduler 208 during periods of transient congestion in the downlink of modem 114.

[0066] In step 10, the egress GbE MAC 324 verifies the frame format, frame length, and FCS of the outgoing frame and updates the associated SNMP MIB counters.

[0067] In step 11, the egress GbE PHY 310 performs SERDES transceiver functions, SERDES framing, byte synchronization / detection, descrambling, 8b / 10b decoding, and 10 / 100 / 1000 auto-negotiation.

[0068] In step 12, the modulator 308 modulates and encodes the received digital PBBN Ethernet frame and transmits the resulting I&Q signal to the IPA for downlink transmission.

[0069] In step 13, terminal 104 (eg, a user terminal or a ground edge terminal) receives the BP-encapsulated PBBN Ethernet frame and begins processing it for transmission to an end user or an information network.

[0070] Migration of terminals from one DFA to another

[0071] Figure 44 is a diagram illustrating an exemplary process for transmitting data for transitioning a terminal 104 from a first communication link 110B to a second communication link 110N. In block 402, a determination is made that a communication terminal 104 is predicted to leave a first communication area 108B served by the first communication link 110B and enter a second communication area 108N served by the second communication link 110N. In block 404, a plurality of data queues 204 associated with the communication terminal 104 are dynamically (e.g., in response to the determination) and losslessly relinked from the first communication link 110B to the second communication link 110N. This can be accomplished, for example, by making changes in an allocation table, such as the FIB 318. As described above, the first communication link 110B includes a first combination of RF beams 106 and channels, and the second communication link includes a second combination of RF beams 106 and channels. In one embodiment, the RF beam 106 and channel combinations are mutually exclusive. That is, a first combination of RF beam 110B and channel serves only a first area 108B, and a second combination of RF beam and channel 110N serves only a second area 108N that is different from the first area.

[0072] The operations of block 402 may be performed by receiving data describing the location of the terminal (e.g., a GPS-derived signal) and predicting that the communication terminal 104 will or has already left the first area 108B and entered the second (and typically adjacent) area 108N. In another embodiment, this is accomplished by monitoring the power of the RF signal of the first communication link 100B and using the monitored RF signal power to predict that the communication terminal 104 will leave the first area 108B and enter the second area 108N (e.g., as indicated by moving from 104B to 104N). As previously described in this disclosure, this uses the sensitivity of the antenna pattern used to transmit and / or receive the RF beam 106 to determine that the terminal 104 is approaching the edge, where the sensitivity is lower than it is at the center of the RF beam 106.

[0073] In one embodiment, the communication terminal 104 has a dedicated subset of the plurality of data queues 204 on the satellite that is not shared with any other communication terminal. Such data queues 204 may include a data queue for each quality of service provided by the terminal 104.

[0074] Figure 5 is a diagram illustrating an exemplary process for dynamically and losslessly relinking all of a plurality of data queues associated with a communication terminal from a first communication link to a second communication link.

[0075] In block 502, queue occupancy data describing occupancy of data queues 204 is received. In block 504, based on the queue occupancy data and the predicted area 108N served by the second communication link 110N, a determination is made to relink all of the data queues 204 associated with the communication terminal 104 from the first communication link 110B to the second communication link 110N. Finally, in block 506, a first group of the plurality of data queues 204 is relinked from the first group of one or more of the plurality of modems 114 to the second group of one or more of the plurality of modems 114.

[0076] Hardware environment

[0077] Figure 6 An exemplary processing system 602 that can be used to implement the processing elements disclosed above is shown, including the switch 112, the MODEM 114, and the DRA controller 254. The processing system 602 includes a processor 604 and memory, such as random access memory (RAM) 606. The processing system 602 operates under the control of an operating system (such as a real-time operating system (RTOS) 608) stored in the memory 606 and interfaces with system elements to accept input data and commands to process the information to generate output data and further commands according to processor instructions included in the application 610. The processing system 602 communicates with other system elements via input / output (I / O bus 630).

[0078] In one embodiment, instructions implementing RTOS 608 , application 610 , and compiler 612 are tangibly embodied in a computer-readable medium, such as memory 606 , which may include hardware memory or firmware memory.

[0079] Additionally, RTOS 608 and computer program 610 consist of instructions that, when read and executed by processing system 602, cause processing system 602 to perform the operations described herein. As used herein, the terms "article of manufacture," "program storage device," and "computer program product" are intended to encompass an application program 610 or operating system 608 accessible from any processing device-readable device or medium.

[0080] Those skilled in the art will recognize that many modifications may be made to this configuration without departing from the scope of this disclosure. For example, those skilled in the art will recognize that any combination of the above components or any number of different components, peripherals, and other devices may be used.

[0081] Furthermore, the present disclosure includes embodiments according to the following clauses:

[0082] Clause 1. A system for transmitting data from a plurality of communication terminals, the plurality of communication terminals including a first communication terminal (104A) served by a first communication link (110A) and a second communication terminal (104B) served by a second communication link (110B), the first communication link (110A) having a combination of beams and channels serving a first area (108A) and the second communication link (110B) having a second combination of beams and channels serving a second area (108B), the system comprising:

[0083] a plurality of modems (114) for receiving uplink data and transmitting downlink data;

[0084] a switch (112) communicatively coupled to a plurality of modems (114), the switch (112) including a plurality of data queues (270), the switch (112) configured to switchably accept uplink data from the plurality of modems (114) and switchably provide downlink data from the plurality of data queues (270) to the plurality of modems (114); and

[0085] a controller (254) communicatively coupled to the plurality of modems (114) and the switch (112), the controller (254) configured to provide controller (254) information operable to control the switch (112) to switchably accept the uplink data from the plurality of modems (114) and switchably provide downlink data from the plurality of data queues (270) to one or more of the plurality of modems (114) on at least one of a per-terminal basis or a per-communications link basis.

[0086] Clause 2. The system of clause 1, wherein the controller (254) information is determined at least in part based on occupancy of the plurality of data queues (270).

[0087] Clause 3. The system of clause 2, wherein:

[0088] said occupancy of said plurality of data queues (270) being determined on a per-terminal basis;

[0089] The controller (254) information includes per-terminal data queue scheduling information;

[0090] The controller (254) includes:

[0091] an uplink controller module (260) configured to receive a request from at least one of the plurality of communication terminals; and

[0092] a downlink controller module (262) configured to generate the per-terminal data queue scheduling information based at least in part on the occupancy of the plurality of data queues (270) and the received requests; and

[0093] The switch (112) includes a per-terminal scheduler configured to switchably provide downlink data from the plurality of data queues (270) to the plurality of modems (114) on a per-terminal basis according to the per-terminal data queue scheduling information.

[0094] Clause 4. The system of clause 3, wherein:

[0095] said occupancy of said plurality of data queues (270) is further determined on a per communication link basis;

[0096] The downlink controller module (262) further generates per-communication link data queue scheduling information based at least in part on the occupancy of the plurality of data queues (270) and the received requests; and

[0097] The switch (112) includes a per-communication link scheduler configured to switchably provide per-terminal scheduled downlink data on a per-communication link basis according to the per-communication link scheduling information.

[0098] Clause 5. The system of clause 4, wherein the uplink controller module (260) is further configured to provide modem configuration data to configure the modem (114) to transmit the downlink data.

[0099] Clause 6. A system according to clause 5, wherein the modem configuration data includes a terminal communication link mapping, which is operable to remap at least one of the per-terminal or per-class service queues from the first communication link (110A) to the second communication link (110B).

[0100] Clause 7. The system of clause 4, wherein the uplink controller module (260) is further configured to provide ingress traffic policing information to the switch (112).

[0101] Clause 8. The system of clause 7, wherein the ingress traffic policing information comprises a per-terminal token bucket filter for marking uplink data as compliant, partially compliant, or noncompliant with a required terminal quality of service.

[0102] Clause 9. The system of clause 1, wherein the switch (112) is further configured to control a modem of the plurality of modems (114) to defer sending uplink data to the switch (112).

[0103] Clause 10. The system of clause 9, wherein the switch (112) is further configured to control the modem to defer receipt of uplink data from the switch (112) via transmission of physical layer data to the modem.

[0104] Clause 11. The system of clause 10, wherein the physical layer data is transmitted via a high-speed bidirectional interface.

[0105] Clause 12. In a system for transmitting data from a first communication terminal (104A) to a second communication terminal (104B), the system comprising: a plurality of modems (114) for receiving uplink data and transmitting downlink data; a switch (112) communicatively coupled to the modems (114), the switch (112) comprising a plurality of data queues (270), the switch (112) for switchably accepting uplink data from the plurality of modems (114) and switchably transmitting downlink data to the plurality of modems (114). 4) providing downlink data; and a controller (254) communicatively coupled to the modems (114) and the switch (112), the controller (254) being configured to control the switch (112) to switchably accept the uplink data from the plurality of modems (114) and switchably provide downlink data from the data queue (270) to the plurality of modems (114). A method of transitioning a communication terminal from a first communication link (110A) to a second communication link (110B), the method comprising:

[0106] determining that the communication terminal is predicted to leave a first area (108A) served by the first communication link (110A) and enter a second area (108B) served by the second communication link (110B); and

[0107] In response to the determination, the plurality of data queues (270) associated with the communication terminal are losslessly relinked from the first communication link (110A) to the second communication link (110B).

[0108] Clause 13. The method of clause 12, wherein:

[0109] providing the uplink data over a first communication link (110A) comprising a first combination of a beam and a channel; and

[0110] The downlink data is provided on a second communication link comprising a second combination of beams and channels.

[0111] Clause 14. The method of clause 13, wherein the first combination of beam and channel serves only a first geographic area and the second combination of beam and channel serves a second geographic area.

[0112] Clause 15. The method of clause 12, wherein determining that the communication terminal is predicted to leave a first area (108A) served by the first communication link (110A) and enter a second area (108B) served by the second communication link (110B) comprises:

[0113] receiving data describing the location of the communication terminal; and

[0114] Based on the received data, it is predicted that the communication terminal will leave the first area (108A) and enter the second area (108B).

[0115] Clause 16. The method of clause 12, wherein determining that the communication terminal is predicted to leave a first area (108A) served by the first communication link (110A) and enter a second area (108B) served by the second communication link (110B) comprises:

[0116] monitoring the power of the signal of the first communication link (110A); and

[0117] Using the power of the monitored signal, it is predicted that the communication terminal will leave the first area (108A) and enter the second area (108B).

[0118] Clause 17. The method of clause 12, wherein the communication terminal has a dedicated subset of the plurality of data queues (270) that is not shared with any other communication terminal.

[0119] Clause 18. The method of clause 12, wherein the plurality of data queues (270) comprises a data queue for each quality of service.

[0120] Clause 19. The method of clause 12, wherein the plurality of data queues (270) are selectably associated with the first communication link (110A) and the second communication link (110B) by a forwarding information base.

[0121] Clause 20. The method of clause 12, wherein losslessly relinking all of the plurality of data queues (270) associated with the communication terminal from the first communication link (110A) to the second communication link (110B) comprises:

[0122] receiving queue occupancy data, the queue occupancy data describing the occupancy of the data queue (270);

[0123] determining said relinking of all of said plurality of data queues (270) associated with said communication terminal from said first communication link (110A) to said second communication link (110B) based on said queue occupancy data and a predicted area served by said second communication link (110B); and

[0124] A first group of the plurality of data queues (270) is relinked from a first group of one or more modems in the plurality of modems (114) to a second group of one or more modems in the plurality of modems (114).

[0125] in conclusion

[0126] The foregoing discloses an apparatus, method, and system for transmitting data from multiple communication terminals, the multiple communication terminals including a first communication terminal served by a first communication link having a combination of beams and channels serving a first area and a second communication terminal served by a second communication link, the first communication link having a combination of beams and channels serving a second area. The apparatus includes: a plurality of modems for receiving uplink data and transmitting downlink data; a switch communicatively coupled to the plurality of modems, the switch including a plurality of data queues, the switch for switchably accepting uplink data from the plurality of modems and switchably providing downlink data from the plurality of data queues to the plurality of modems; and a controller communicatively coupled to the plurality of modems and the switch, the controller for providing controller information for dynamically controlling the switch to switchably accept uplink data from the plurality of modems and switchably provide downlink data from the plurality of data queues to one or more of the plurality of modems on a per-terminal and per-communication link basis.

[0127] Implementations may include one or more of the following features:

[0128] Any apparatus described herein, wherein the controller information is determined at least in part based on occupancy of the plurality of data queues.

[0129] Any apparatus described herein, wherein occupancy of the plurality of data queues is determined on a per-terminal basis; the controller information comprises per-terminal data queue scheduling information; the controller comprises: an uplink controller module for receiving requests from the plurality of communication terminals; and a downlink controller module for generating the per-terminal data queue scheduling information based at least in part on the occupancy of the plurality of data queues and the received requests.

[0130] Any apparatus described herein, wherein the switch comprises a per-terminal scheduler for switchably providing downlink data from the plurality of data queues to the plurality of modems on a per-terminal basis according to the per-terminal data queue scheduling information.

[0131] Any apparatus described herein, wherein occupancy of the plurality of data queues is further determined on a per-communication link basis; the downlink controller module further generates per-communication link data queue scheduling information based at least in part on the occupancy of the plurality of data queues and the received requests; and the switch includes a per-communication link scheduler for switchably providing per-terminal scheduled downlink data on a per-communication link basis based on the per-communication link scheduling information.

[0132] Any apparatus described herein, wherein the uplink controller module further provides modem configuration data to configure the modem to transmit downlink data.

[0133] Any apparatus described herein, wherein the modem configuration data includes a terminal communication link mapping for dynamically remapping a per-terminal / per-class-of-service queue from a first communication link to a second communication link.

[0134] Any apparatus as described herein, wherein the uplink controller module further provides ingress traffic policing information to the switch.

[0135] Any apparatus as described herein, wherein the ingress traffic policing information comprises a per-terminal token bucket filter for marking uplink data as compliant, partially compliant, or non-compliant with a required terminal quality of service.

[0136] Any apparatus described herein, wherein the switch further controls each modem of the plurality of modems to defer sending uplink data to the switch.

[0137] Any apparatus described herein, wherein the switch controls each modem of the plurality of modems to defer receipt of uplink data from the switch via transmission of physical layer data to the modem.

[0138] Any apparatus described herein, wherein physical layer data is transmitted via a high-speed bidirectional interface.

[0139] Another embodiment is demonstrated by a method for transitioning a communication terminal from a first communication link to a second communication link, and a system for transmitting data from the first communication terminal to the second communication terminal, the system comprising: a plurality of modems for receiving uplink data and transmitting downlink data; a switch communicatively coupled to the modems, the switch comprising a plurality of data queues, the switch for switchably accepting uplink data from the plurality of modems and switchably providing downlink data to the plurality of modems; and a controller communicatively coupled to the modems and the switch, the controller for controlling the switch to switchably accept uplink data from the plurality of modems and switchably provide downlink data from the data queues to the plurality of modems. The method comprises: determining that the communication terminal is predicted to leave a first area served by the first communication link and enter a second area served by the second communication link; and responsive to the determination, dynamically and losslessly relinking the plurality of data queues associated with the communication terminal from the first communication link to the second communication link.

[0140] Implementations may include one or more of the following features:

[0141] Any method described herein, wherein uplink data is provided on a first communication link comprising a first combination of beams and channels; and downlink data is provided on a second communication link comprising a second combination of beams and channels.

[0142] Any method described herein, wherein a first combination of beams and channels serves only a first geographic area, and a second combination of beams and channels serves a second geographic area.

[0143] Any method described herein, wherein determining that a communication terminal is predicted to leave a first area served by a first communication link and enter a second area served by a second communication link comprises: receiving data describing a location of the communication terminal; and based on the received data, predicting that the communication terminal will leave the first area and enter the second area.

[0144] Any method described herein, wherein determining that a communication terminal is predicted to leave a first area served by a first communication link and enter a second area served by a second communication link comprises: monitoring the power of a signal of the first communication link; and using the power of the monitored signal, predicting that the communication terminal will leave the first area and enter the second area.

[0145] Any method described herein, wherein the communication terminal has a dedicated subset of the plurality of data queues that is not shared with any other communication terminal.

[0146] Any method described herein, wherein the plurality of data queues comprises a data queue for each quality of service.

[0147] Any of the methods described herein, wherein the plurality of data queues are selectably associated with the first communication link and the second communication link by a forwarding information base.

[0148] Any method described herein, wherein dynamically and losslessly relinking all of a plurality of data queues associated with a communication terminal from a first communication link to a second communication link comprises: receiving queue occupancy data, the queue occupancy data describing occupancy of the data queues; determining, based on the queue occupancy data and a predicted area served by the second communication link, to relink all of the plurality of data queues associated with the communication terminal from the first communication link to the second communication link; and relinking a first group of the plurality of data queues from a first group of one or more of a plurality of modems to a second group of one or more of the plurality of modems.

[0149] Any method described herein, wherein the method further comprises filtering the queue occupancy data according to a low pass filter. The method may also comprise a cross-layer design for closed-loop feedback in a wireless network.

[0150] The foregoing description of the preferred embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Many modifications and variations are possible in light of the above teachings. It is intended that the scope of the rights be limited not by this detailed description, but rather by the appended claims.

Claims

1. A system for transmitting data from a plurality of communication terminals, the plurality of communication terminals comprising a first communication terminal (104A) served by a first communication link (110A) and a second communication terminal (104B) served by a second communication link (110B), the first communication link (110A) having a combination of beams and channels serving a first area (108A), and the second communication link (110B) having a second combination of beams and channels serving a second area (108B), the system comprising: a plurality of modems (114) for receiving uplink data and transmitting downlink data; a switch (112) communicatively coupled to a plurality of modems (114), the switch (112) including a plurality of data queues (270), the switch (112) configured to switchably accept uplink data from the plurality of modems (114) and switchably provide downlink data from the plurality of data queues (270) to the plurality of modems (114); as well as a controller (254) communicatively coupled to the plurality of modems (114) and the switch (112), the controller (254) configured to provide controller (254) information operable to control the switch (112) to switchably accept the uplink data from the plurality of modems (114) and switchably provide downlink data from the plurality of data queues (270) to one or more of the plurality of modems (114) on at least one of a per-terminal basis or a per-communications link basis, wherein the system is configured to: determining that the communication terminal is predicted to leave a first area (108A) served by the first communication link (110A) and enter a second area (108B) served by the second communication link (110B); and In response to the determination, losslessly relinking the plurality of data queues (270) associated with the communication terminal from the first communication link (110A) to the second communication link (110B), wherein losslessly relinking all of the plurality of data queues (270) associated with the communication terminal from the first communication link (110A) to the second communication link (110B) comprises: receiving queue occupancy data, the queue occupancy data describing the occupancy of the data queue (270); determining said relinking of all of said plurality of data queues (270) associated with said communication terminal from said first communication link (110A) to said second communication link (110B) based on said queue occupancy data and a predicted area served by said second communication link (110B); and A first group of the plurality of data queues (270) is relinked from a first group of one or more modems in the plurality of modems (114) to a second group of one or more modems in the plurality of modems (114).

2. The system of claim 1, wherein the controller (254) information is determined at least in part based on occupancy of the plurality of data queues (270).

3. The system of claim 2, wherein: said occupancy of said plurality of data queues (270) being determined on a per-terminal basis; The controller (254) information includes per-terminal data queue scheduling information; The controller (254) includes: an uplink controller module (260) configured to receive a request from at least one of the plurality of communication terminals; as well as a downlink controller module (262) configured to generate the per-terminal data queue scheduling information based at least in part on the occupancy of the plurality of data queues (270) and the received requests; and The switch (112) includes a per-terminal scheduler configured to switchably provide downlink data from the plurality of data queues (270) to the plurality of modems (114) on a per-terminal basis according to the per-terminal data queue scheduling information.

4. The system of claim 3, wherein: said occupancy of said plurality of data queues (270) is further determined on a per communication link basis; The downlink controller module (262) further generates per-communication link data queue scheduling information based at least in part on the occupancy of the plurality of data queues (270) and the received requests; and The switch (112) includes a per-communication link scheduler configured to switchably provide per-terminal scheduled downlink data on a per-communication link basis according to the per-communication link data queue scheduling information.

5. The system of claim 4, wherein the uplink controller module (260) is further configured to provide modem configuration data to configure the modem (114) to transmit the downlink data.

6. The system of claim 5, wherein the modem configuration data includes a terminal communication link map, the terminal communication link map being operable to remap at least one of the per-terminal or per-class service queues from the first communication link (110A) to the second communication link (110B).

7. The system of claim 4, wherein the uplink controller module (260) is further configured to provide ingress traffic policing information to the switch (112).

8. The system of claim 7, wherein the ingress traffic policing information includes a per-terminal token bucket filter for marking uplink data as compliant, partially compliant, or noncompliant with a required terminal quality of service.

9. The system of claim 1, wherein the switch (112) is further configured to control a modem of the plurality of modems (114) to defer sending uplink data to the switch (112).

10. The system of claim 9, wherein the switch (112) is further configured to control the modem to defer receipt of uplink data from the switch (112) via transmission of physical layer data to the modem.

11. The system of claim 10, wherein the physical layer data is transmitted via a high-speed bidirectional interface.

12. In a system for transmitting data from a first communication terminal (104A) to a second communication terminal (104B), the system comprises: a plurality of modems (114) for receiving uplink data and transmitting downlink data; a switch (112) communicatively coupled to the modems (114), the switch (112) comprising a plurality of data queues (270), the switch (112) for switchably accepting uplink data from the plurality of modems (114) and switchably providing downlink data to the plurality of modems (114); and a controller (254) communicatively coupled to the modems (114) and the switch (112), the controller (254) being configured to control the switch (112) to switchably accept the uplink data from the plurality of modems (114) and switchably provide downlink data from the data queue (270) to the plurality of modems (114). A method of transitioning a communication terminal from a first communication link (110A) to a second communication link (110B), the method comprising: determining that the communication terminal is predicted to leave a first area (108A) served by the first communication link (110A) and enter a second area (108B) served by the second communication link (110B); and In response to the determination, losslessly relinking the plurality of data queues (270) associated with the communication terminal from the first communication link (110A) to the second communication link (110B), wherein losslessly relinking all of the plurality of data queues (270) associated with the communication terminal from the first communication link (110A) to the second communication link (110B) comprises: receiving queue occupancy data, the queue occupancy data describing the occupancy of the data queue (270); determining said relinking of all of said plurality of data queues (270) associated with said communication terminal from said first communication link (110A) to said second communication link (110B) based on said queue occupancy data and a predicted area served by said second communication link (110B); and A first group of the plurality of data queues (270) is relinked from a first group of one or more modems in the plurality of modems (114) to a second group of one or more modems in the plurality of modems (114).

13. The method according to claim 12, wherein: providing the uplink data over a first communication link (110A) comprising a first combination of a beam and a channel; and The downlink data is provided on a second communication link comprising a second combination of beams and channels.

14. The method of claim 13, wherein the first combination of beam and channel serves only a first geographic area, and the second combination of beam and channel serves a second geographic area.

15. The method of claim 12, wherein determining that the communication terminal is predicted to leave a first area (108A) served by the first communication link (110A) and enter a second area (108B) served by the second communication link (110B) comprises: receiving data describing the location of the communication terminal; as well as Based on the received data, it is predicted that the communication terminal will leave the first area (108A) and enter the second area (108B).

16. The method of claim 12, wherein determining that the communication terminal is predicted to leave a first area (108A) served by the first communication link (110A) and enter a second area (108B) served by the second communication link (110B) comprises: monitoring the power of the signal of the first communication link (110A); as well as Using the power of the monitored signal, it is predicted that the communication terminal will leave the first area (108A) and enter the second area (108B).

17. The method of claim 12, wherein the communication terminal has a dedicated subset of the plurality of data queues (270) that is not shared with any other communication terminal.

18. The method of claim 12, wherein the plurality of data queues (270) includes a data queue for each quality of service.

19. The method of claim 12, wherein the plurality of data queues (270) are selectably associated with the first communication link (110A) and the second communication link (110B) by a forwarding information base.

20. In a system for transmitting data from a first communication terminal to a second communication terminal, the system comprises: a plurality of modems for receiving uplink data and transmitting downlink data; a switch communicatively coupled to the modems, the switch comprising a plurality of data queues, the switch for switchably accepting uplink data from the plurality of modems and switchably providing downlink data to the plurality of modems; and a controller communicatively coupled to the modems and the switch, the controller being configured to control the switch to switchably accept the uplink data from the plurality of modems and switchably provide downlink data from the plurality of data queues to the plurality of modems. An apparatus for transitioning a communication terminal from a first communication link to a second communication link, the apparatus comprising: means for determining that the first communication terminal is predicted to leave a first area served by the first communication link and enter a second area served by the second communication link; and means for losslessly relinking the plurality of data queues associated with the first communication terminal from the first communication link to the second communication link in response to the determination; wherein the first communication terminal has a dedicated set of the plurality of data queues that is not shared with the second communication terminal, and losslessly relinking the plurality of data queues associated with the first communication terminal from the first communication link to the second communication link comprises dynamically remapping the dedicated set of data queues from the first communication link to the second communication link.

21. The apparatus of claim 20, wherein: providing the uplink data over the first communication link comprising a first combination of a beam and a channel; and The downlink data is provided over the second communication link comprising the second combination of the beam and channel.

22. The apparatus of claim 21, wherein the first combination of beam and channel serves only a first geographic area, and the second combination of beam and channel serves a second geographic area.

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