Abstract: An approach is provided for processing structure Low Density Parity Check (LDPC) codes. Memory storing edge information and a posteriori probability information associated with a structured parity check matrix used to generate Low Density Parity Check (LDPC) coded signal are accessed. The edge information represent relationship between bit nodes and check nodes, and are stored according to a predetermined scheme that permits concurrent retrieval of a set of the edge information.

Abstract: An approach is provided for shaping traffic of a communication system. Resource usage of a network element of the communication system is determined. The usage is compared with thresholds that are established according to loading of the communication system; these thresholds correspond to various transmission states that limit usage of the resources of the communication system (e.g., bandwidth). Further, based on the comparison, the resource usage of the network element is controlled according to a particular transmission state, thereby ensuring fair access. This approach as particular applicability to shared capacity systems, such as a satellite communication system.

Abstract: An approach is provided for obtaining load of a terminal operating in a communication system. A query is transmitted for a cumulative load of the terminal, wherein the terminal belongs to a group of terminals having a common service level. The cumulative load for the terminal is determined based on load information supplied by the terminal and bandwidth allocation information, wherein the cumulative load represents a total amount of data sent over a communication channel of the communication system. The determined cumulative load is provided in response to the query. This arrangement has particular applicability to a satellite network that provides data communication services.

Abstract: An approach is provided for supporting retrieval of web content over a meshed communication network (111). A first server (105) receives a request from a browser application (103) for the content resident in the web server (109). The first server (105) includes a downstream proxy (401) configured to modify the request to include information specifying support of a parse and pre-fetch service within an optional header field of the request as to permit handling of the modified request by the web server (109) in absence of an upstream proxy (403) that is communicating with the web server (109). A second server (107) is configured as the upstream proxy (403) to intercept the modified request and pre-fetch the content from the web server (109). The second server (107) forwards the pre-fetched content over the communication network (111) to the first server (105). This approach has particular applicability in relatively high latency networks, such as a satellite communications system.

Abstract: The present invention provides a communication system for use with a first source signal and a second source signal. The first source signal is on a first channel and includes M symbols, where M is an integer greater than 1. The second source signal is on a second channel and includes X symbols, where X is an integer greater than 1. The first channel is different from the second channel. The communication system includes a first modulator unit, a second modulator unit and an adder. The first modulator unit can generate a first modulated signal based on the first source signal and includes a first inter-symbol distortion estimating unit and a first stage predistortion unit. The second modulator unit can generate a second modulated signal based on the second source signal and includes a second inter-symbol distortion estimating unit and a predistortion unit. The adder can generate an added signal based on the first modulated signal and the second modulated signal.

Abstract: A device is provided for use with an input signal including a first packet of a first modulation type in series with a second packet of a second modulation type. The device includes a gain adjustment portion and a gain portion. The gain adjustment portion can output a first gain adjustment signal based on the first packet or can output a second gain adjustment signal based on the second packet. The gain portion can output a first signal corresponding to the first packet and can output a second signal corresponding to the second packet. The first signal is based on the input signal and a first gain factor. The second signal is based on the input signal and a second gain factor. The first gain factor is based on the first gain adjustment signal. The second gain factor is based on the second gain adjustment signal.

Abstract: A system in which a personal computer sends messages into a TCP/IP network using a conventional dial-up link and downloads data from the TCP/IP network using a high-speed one-way satellite link. A preferred embodiment uses a conventional SLIP provider to connect to the TCP/IP network and uses a commercial software TCP/IP package that has a standard driver interface. A spoofing protocol compensates for the long propagation delays inherent to satellite communication.

Abstract: An aspect of the present invention is drawn to a receiver operable to receive a first signal transmitted on a first carrier and to receive a second signal transmitted on a second carrier. The receiver includes a first filter, a second filter and a nonlinear compensator. The first filter is arranged to receive the first signal and to generate a first filtered signal. The second filter is arranged to receive the second signal and to generate a second filtered signal. The nonlinear compensator is arranged to output a first compensating signal based on the first filtered signal and the second filtered signal and to output a second compensating signal based on the first filtered signal and the second filtered signal. Further, the nonlinear compensator can reduce one of nonlinear interference within the first filtered signal and nonlinear interference between the first filtered signal and the second filtered signal.

Abstract: A multiple access scheme is described. One or more encoders are configured to encode a plurality of bit streams using Low Density Parity Check (LDPC) coding. The bit streams correspond to a respective plurality of terminals. The plurality of bit streams are converted to provide a multiple access scheme for the terminals.

Abstract: An approach is provided for graceful shutdown and startup of spoofing when a handover procedure is performed. A handover of a performance enhancing proxy (PEP) session associated with a transport connection is detected. A shutdown procedure is initiated to stop spoofing of the transport connection in response to the detected handover. The shutdown procedure avoids teardown of the transport connection during the handover from a first link to a second link of a communication system.

Abstract: An approach provides a satellite air interface to efficiently support communication with a terrestrial network. One or more packets associated with a data communication session are received from a terrestrial network configured to provide cellular communications. A frame representing the packet for transmission is generated over a satellite link to a user terminal. Signaling information for the transmission of the packet over the terrestrial network is modified or eliminated for transmission over the satellite link.

Abstract: Requests for secure content are rewritten before delivering the secure content to a client. In one implementation, the rewritten requests include the information content from the original request with the addition of a predetermined domain. The domain may correspond to a trusted agent that acts as a proxy for all secure requests from the client. Because of the rewritten request, the trusted agent is contacted by the client for the secure content. The trusted agent may then transparently (from the point of view of the client) retrieve and forward the secure content to the client.

Abstract: An approach for providing secure access to inroutes or return channels in a radio communication system including a hub communicating with terminals is disclosed. A quality of service level (QoS) corresponding to one of the terminals is determined. An identifier is assigned to the one terminal for communicating over a set of return channels that are in the direction of the one terminal to the hub. The identifier associates a subset of the terminals with the QoS level; the subset includes the one terminal. This arrangement has particular applicability to a satellite network that provides data communication services.

Abstract: A method, system, and computer program product for providing communications services, including determining a type of communications service present in a communications session based on quality of service parameters assigned for the communications session; and adjusting the quality of service parameters based a different type of communications service requested. The types of communications services include real-time and non-real-time communications services.

Abstract: A method, system, apparatus and computer program product for correcting errors in a signal transmission using a rate ¾ low density parity check (LDPC) code. At least a portion of a received data message is encoded by using a parity check matrix of the LDPC code. The encoded data message is transmitting in a signal transmission over a communication channel to a receiving device in the communication network. After being received, the encoded portion of the data message is decoded using a parity check matrix of the LDPC code to obtain the data message. For example, the encoding and decoding can be performed using a parity check matrix corresponds to a coded block size (N) equal to 1944 for communicating data in compliance with an 802.11n standard.

Abstract: A multiple access scheme is described. A first bit stream is scrambled from a first terminal according to a first scrambling signature. A second bit stream is scrambled from a second terminal according to a second scrambling signature, wherein the first bit stream and the second bit stream are encoded using a low rate code. The first scrambling signature and the second scrambling signature are assigned, respectively, to the first terminal and the second terminal to provide a multiple access scheme.

Abstract: An approach is provided for adapting multicast services originating from a terrestrial network over a satellite network. A request for establishing a multicast session corresponding to a network address of the terrestrial network is received at a hub station. The request specifies participating satellite terminals in the multicast session. The hub station assigns an address unique within the satellite network to map to the network address for the multicast session. The participating satellite terminals are configured with the assigned satellite address. A distribution mechanism is selected to transport dataflow of the multicast session to the participating satellite terminals. The distribution mechanism utilizes one or more spot beams covering the participating satellite terminals, wherein the selected distribution mechanism is switched to another one of the distribution mechanisms based on capacity of the satellite network and reachability of the participating satellite terminals.

Abstract: An approach for transmitting packets over a shared communication channel is disclosed. A satellite terminal (ST) (103, 105, 107, 109) contains a processor that transmits a packet over a transmission slot of the channel using a contention protocol, such as persistent Aloha. The processor reserves an available transmission slot, which is maintained until expiration of a predetermined timeout period.

Abstract: A two-way satellite communication system for providing a scalable architecture is disclosed. A plurality of transceivers transmit signals over a plurality of return channels, wherein the plurality of return channels are partitioned into a plurality of return channel groups. A hub communicates with the plurality of transceivers via the plurality of return channel groups. The hub is connected to a packet switched network. Each of the plurality of transceivers performs a random weighted selection of a return channel group among the plurality of return channel groups.

Abstract: A method and system are provided for allocating satellite resources in a satellite communication system. A network interface is provided for making requests for satellite resources. A request processor determines whether the requests can be fulfilled based on a plurality of system constraints. The constraints can include, for example, the number of antennas on board the satellite, the number of active demodulators available on board the satellite, the configuration of a switch matrix which connects antennas to demodulators, and interference between signals transmitted to and from neighboring geographic cells. The network interface is preferably implemented in a web browser connected to a network which includes the Internet.