Northrop Grumman Systems Corporation

Trw Limited

Lincom Corporation

Jaime L Prieto, Jr

Darren R Gregoire

Gefferie H Yee-Madera

Jason R Kincaid

David A Wright

Stuart T Linsky

Oliver W Saunders

Scott M Takahashi

Roland Y Wong

Lisa A Moy-Yee

Scott L Wilkinson

A method and apparatus for scheduling, in real-time, the order in which data packets from multiple uplink channels are organized in a downlink channel of a satellite communications network. The satellite includes uplink and downlink channels for conveying data packets over channels between user terminals, ground stations and other user terminals. Queues in the satellite collect data packets from uplinks and output the data packets to the downlink using a bandwidth that is dynamically allocated. A scheduler allocates the bandwidth to at least one queue and continuously changes the amount of bandwidth allocated to each active queue while the queue is buffering data packets between the uplinks and downlink. The scheduler allocates bandwidth based upon a priority-class packet service schedule calculated based upon traffic parameters associated with each active queue.

Method and apparatus for real time scheduling in a satellite communications network

A downlink scheduler ( ) is provided for scheduling the downlink transmission of data cells in a spot beam processing satellite ( ). The downlink scheduler ( ) includes a beam selector ( ) for selecting one of the spot beams associated with the satellite ( ), a plurality of wholesale selectors ( ) for selecting one of a plurality of wholesalers, such that each of the wholesale selectors ( ) is associated with one of the spot beams, and a plurality of retail selectors ( ) for selecting one of a plurality of retail connections, such that each of the retail selectors ( ) is associated with one of the wholesalers. Each of the selectors may use a packet fair queuing (PFQ) method to make its selection. The downlink scheduler ( ) then passes at least one data cell from a selected retail connection to a downlink modulator ( ), thereby scheduling the downlink transmission of data cells in the satellite.

Hierarchical downlink scheduler for a processed satellite payload

A method and apparatus for implementing multicast in a space-based communication system is disclosed. The present invention allows for the use of a buffer in which to store data packets prior to replication in a multicast application. The present apparatus includes a buffer ( ), a header memory ( ), and an ASIC ( ) to store and extract received data packets and replicate them as required. The ASIC ( ) includes a switch interface ( ), a queue manager ( ), a header processor ( ), a holding buffer ( ), and a arbitration interface ( ). The switch interface ( ) is connected to the queue manager ( ). The queue manager ( ) is connected to the buffer ( ), the header processor , the holding buffer ( ), and the arbitration and switch interface ( ). The header processor ( ) is connected to the header memory ( ). The header processor ( ) and the holding buffer ( ) are connected to an arbitration and switch interface ( ), whose output, in turn, is fed back through the switch matrix routing fabric ( ) for routing and eventual downlink transmission. The method includes the steps of receiving data packets from the switch matrix routing fabric ( ); storing the information payload and the header in the buffer( ); and extracting the information payload and header from the buffer ( ). The method further includes the steps of buffering the information payload to the holding buffer ( ); provisioning the header to the header processor ( ); addressing the header memory ( ); merging the new header obtained from the header memory with the information payload ( ); and performing subsequent processing on the assembled cell ( ). The latter two steps are repeated until all replicated cells are assembled and sent on for routing and eventual downlink transmission.

Method and apparatus for serial cell replication for multicast in a cell switch

A distributed demand assigned multiple access control scheme for use in connection with a processing satellite communications system, where multiple users are assigned to a common transmission resource as part of a sharing set. The control scheme of the invention makes use of a reservation procedure by transmitting set addressed reservation messages in a contentious control flow to reserve data transfer time in a non-contentious main flow. Each user of the sharing set is synchronized to the next available uplink time slot available to transmit data in the main flow. If a transmitted reservation message is returned in the satellite downlink, the terminal knows that all of the users of the set received the message. That reserved time interval in the main flow Is now owned by that user, and each user in the shared set updates its next available uplink time slot based on the reserved time.

Distributed control DAMA protocol for use with a processing communications satellite

The present invention is a method and apparatus for processing data packets in the outbound module of a space-based cell switch. The present invention uses an expanded set of queuing parameters to determine an output queue in which to store each data packet. The method includes the steps of selecting an expanded set of queuing parameters ( ), establishing several output queues ( ) based on combinations of the expanded set of queuing parameters, receiving data packets in a communications uplink ( ), examining the header portion of each received data packet ( and ), determining an appropriate output queue in which to store the data packet ( and ), and switching the received data packets to that appropriate output queue ( ). The present apparatus includes several input modules ( ), a switch control output ( ) connected between the input module ( ) and a switch fabric ( ), and a several output modules ( ) connected to the switch fabric ( ). The input modules ( ) each include a discriminator circuit ( ) distinguishing among several combinations of queuing parameters from an expanded set of queuing parameters, and the output modules ( ) each include several output queues ( ) and a cell selector ( ) for selecting the destination output queue in which to store each data packet.

Queue segmentation and addressing method and apparatus for a cell switch in a processing communications satellite

Techniques for trading satellite communication resources include a net work operations controller for receiving an offer and analyzing bids in response to the offer. The network operations controller at least partially revises a downlink schedule of resources in response to the winning bid. A satellite receives information from the network operations controller and configures a switch in the satellite, as well as the downlink schedule, in order to enable data communications through the satellite by the winning bidder.

Communication satellite resource trading techniques

A mapping scheme that maps standard ATMs service classes ( ) of the type used in a wired communications network into one of a plurality of available media access control channels ( ) that allow the particular ATM service class ( ) to be transmitted efficiently over the network, such as a satellite network. The various media access controlled channel types ( ) reside in a media access control layer ( ) between the ATM layer ( ) and the physical layer ( ). A predetermined uplink user protocol is assigned to each MAC channel to efficiently transmit to the ATM cells on the satellite uplink.

Media access control layer for satellite ATM networks

An onboard DAMA protocol for use in connection with a processing satellite communications network, where multiple users are assigned to a common transmission resource as part of a sharing set. A media access controller ( ) on the satellite maintains a reservation log which identifies the frequencies and number of uplink time slots in the resource that are currently reserved by one or more members of the sharing set. To reserve a time-frequency slot on the transmission resource for a non-contentious transmission of data, a user of the sharing set will transmit a reservation request to the satellite on a contentious uplink resource. If a return message is not received, the user knows that the reservation request collided with another reservation request, and a retransmission strategy of the reservation request is employed. When the media access controller ( ) receives the reservation request, it decides whether to grant, deny or delay the request based on the service and price class of the user, the amount of data already sent by the user, the number and type of other users with reservation requests in the queue, and the congestion state of the destination downlink port and subsequent nodes in the network. When the user receives a reservation grant message from the media access controller ( ) on the satellite in the downlink, it will then wait for its reservation time frequency slot, and transmit its data in a non-contentious basis on the transmission resource at that time. If the user needs additional bandwidth to transmit more data, it may piggyback a reservation request on the data transfer.

Onboard control of demand assigned multiple access protocol for satellite ATM networks

A method and device for extrapolating past signal-history data for insertion into missing data segments in order to conceal digital speech frame errors. The extrapolation method uses past-signal history that is stored in a buffer. The method is implemented with a device that utilizes a finite-impulse response (FIR) multi-layer feed-forward artificial neural network that is trained by back-propagation for one-step extrapolation of speech compression algorithm (SCA) parameters. Once a speech connection has been established, the speech compression algorithm device begins sending encoded speech frames. As the speech frames are received, they are decoded and converted back into speech signal voltages. During the normal decoding process, pre-processing of the required SCA parameters will occur and the results stored in the past-history buffer. If a speech frame is detected to be lost or in error, then extrapolation modules are executed and replacement SCA parameters are generated and sent as the parameters required by the SCA. In this way, the information transfer to the SCA is transparent, and the SCA processing continues as usual. The listener will not normally notice that a speech frame has been lost because of the smooth transition between the last-received, lost, and next-received speech frames.

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Torrance, CA, United States of America

Jaime L Prieto, Jr