770 results about "Multicast transmission" patented technology

A method of multicasting a data file. The method includes transmitting a notification on an upcoming multicast transmission to a plurality of receivers (20) designated to receive the multicast transmission, tuning by at least one of the plurality of receivers (20) to one or more multicast channels, responsive to the notification, transmitting a data file, from a data server (42), on the one or more multicast channels, without the data server (42) receiving acknowledgements from the receivers (20) on whether they received the notification, determining receivers (20) designated to receive the multicast transmission that did not receive at least a portion of the data file; and attempting to deliver the data file to the determined receivers (20).

A novel and useful media access control (MAC) protocol that is intended for use over noisy shared media channels. The MAC protocol provides layer 2 functionality over a network using a shared medium including a backoff mechanism for CSMA/CA channel access, link addressing that reduces the overhead of long MAC addresses, a flooding scheme having controlled exposure for broadcast transmissions, multicast transmissions using selective ACKs, implementation of traffic prioritization using an adaptive backoff scheme, a second layer repeater establishment process and multi-packet transport for short packets and fragmentation for long packet transport.

Disclosed are systems and methods which provide high bandwidth data communication with respect to a large coverage area using smart antenna and/or directional antenna (referred to herein as multi-beam antenna) technology. Circuitry may be provided at a WLAN AP to provide selection of particular antenna beams used in the downlink and/or uplink, control of multicast transmission, control of unicast transmission, and to provide antenna pattern shaping techniques. Embodiments implement multi-beam antenna technology with little or no hardware modifications to AP circuitry. Other embodiments implement multi-beam technology using radio front-end and/or radio hardware modifications to AP circuitry. Various diversity techniques may be implemented, such as selection diversity, maximum ratio combining, and equal gain combing. To provide desired antenna pattern shaping, phase offsets with respect to a signal as transmitted in each antenna beam may be employed.

A method of monitoring a computer system, by detecting a power interruption to the computer system, using power down sense logic, and generating an alert associated with the power interruption. When the computer system is networked, the alert is transmitted to a remote server. The power down sense logic sends a message to an auxiliary processor (which may be an application-specific integrated circuit, or ASIC), and the auxiliary processor creates a network transmission packet indicating that the computer system is losing power. The auxiliary processor may allow selection of a transmission mode such as uni-cast transmission, multi-cast transmission, or broadcast transmission. A common power supply provides a first power signal to the computer system, and a second power signal to the power down sense logic and auxiliary processor, and maintains the second power signal for a longer duration than the first power signal upon removal of a power source for the power supply, sufficient to carry out the sending of the message from the power down sense logic and the creating of the network alert.

Secure tunneled multicast transmission and reception through a network is provided. A join request may be received from a second tunnel endpoint, the join request indicating a multicast group to be joined. Group keys may be transmitted to the second tunnel endpoint, where the group keys are based at least on the multicast group. A packet received at the first tunnel endpoint may be cryptographically processed to generate an encapsulated payload. A header may be appended to the encapsulated payload to form an encapsulated packet, wherein the header includes information associated with the second tunnel endpoint. A tunnel may be established between the first tunnel endpoint and the second tunnel endpoint based on the appended header. The encapsulated packet may be transmitted through the tunnel to the second tunnel endpoint. The second tunnel endpoint may receive the encapsulated packet. Cryptographic processing of the encapsulated packet may reveal the packet having a second header. The packet may then be forwarded on an interface toward at least one multicast recipient identified in the second header.

Systems and methodologies are described that facilitate remotely monitoring and/or controlling a media device that obtains broadcast and/or multicast transmission(s). According to various aspects, systems and methods are described that facilitate remotely controlling media device(s) that operate in connection with broadcast and/or multicast transmission(s) with limited or no reverse link (e.g., employing Forward Link Only (FLO) technology, . . . ). Such systems and methods may monitor various service issues, device performance, network performance, and the like.

A method of establishing a multicast transfer route is disclosed that can reduce the cost of entire route under a constraint on delay incurred between starting point and ending points. The method includes the steps of: computing the shortest route with respect to delay connecting the starting point and the plural ending points based on measurement result; computing delay from a node on the shortest route to each ending point and the greatest delay; removing, if the greatest delay satisfies a delay condition, the greatest-cost route from the shortest route in accordance with selection criteria effective for cost reduction; dividing the multicast transfer route into two route trees; and establishing separately computed route as a complementary route that complement the removed route for connecting the two route trees. A method of multicast label switching for realizing the above method is also disclosed. A multicast label switching route is established using hierarchical labels by establishing a common multicast label switching route using a first layer label and establishing plural partial multicast label switching routes for subgroup destinations using lower layer labels. A relay node recognizes the hierarchical labels thereby to label-switch using all hierarchical labels.

A multicasting system for reception of multimedia information comprising: a content switch coupled to a multimedia content source and at least one multimedia smart terminal. The multimedia content source includes a plurality of multimedia contents, wherein each multimedia content is supported by a primary multimedia stream transmitted over a primary dedicated channel having a primary bandwidth. At least one multimedia smart terminal is configured to receive from the content switch over a network each multimedia content as a secondary multimedia stream transmitted over a secondary channel having a secondary bandwidth. The content switch includes a bandwidth scaler configured to scale each primary multimedia stream to a plurality of secondary multimedia sub-streams that are substantially synchronized. The multimedia smart terminal includes a smart terminal sub-stream switch configured to switch among the plurality of secondary multimedia sub-streams in order to select a substantially optimum secondary multimedia sub-stream. The substantially optimum secondary multimedia sub-stream includes a substantially optimum relationship between an error rate level determined at the time of reception of a multimedia content and the quality of reception of a multimedia content.

A high speed downlink packet access base station (HSPDA Node B) and a method therefore working in acknowledged mode (AM), the base station being adapted for unicast transmission on a physical downlink shared channel (HS-DSCH), by preceding announcement on a shared control channel (HS-SCCH) which shared control channel may be decoded by a given user entity using its own identity (UE-ID), each user entity (UE) being adapted for transmitting an acknowledge (ACK) or non-acknowledge (NACK) message pertaining to the reception of the given transmission on an uplink dedicated physical control channel (HS-DPCCH) pertaining to a given HARQ process of a given individual user entity. The base station is performing multicast transmissions (11, 401) on the physical downlink shared channel (HS-DSCH) by preceding announcement on the shared control channel (HS-SCCH) coded with a multicast identity (MU-ID) of a reserved address space, which downlink shared channel (HS-SCCH) may be decoded simultaneously by a plurality of user entities, wherein each user entity is using the multicast identity (MU-ID) instead of the user entity's respective user identity. A user entity and a method therefore have moreover been provided.

A method is described for receiving a multicast in user devices in a network issuing a request to join a multicast group, identifying multicast data packets associated with the multicast group, monitoring transmissions of the multicast data packets to determine whether the identified multicast data packets are being transmitted in an already established unicast session and establishing a unicast session and processing multicast data packets if an already established unicast session does not exist A method is described for receiving a multicast transmission in user devices in a network establishing a unicast session with a dedicated terminal, identifying multicast data packets associated with a multicast group, monitoring transmissions of the multicast data packets and processing the multicast data packets by the dedicated terminal. Additonally, an apparatus is described for accepting a request to join a multicast group, for identifying multicast data packets associated with the multicast group, establishing a unicast session, for encapsulating said multicast data packets in a unicast frame and for forwarding the unicast frame via the unicast session.

A method of multicasting data. The method includes providing a data block for multicasting, generating a plurality of segments that represent the data block, such that a receiver needs to receive fewer than all the generated segments in order to reconstruct the data block, encrypting at least a portion of the generated segments, so as to generate encrypted data units encrypted with a plurality of different keys or encryption methods and transmitting the encrypted data units over one or more multicast channels.

A broadband communication system with improved latency is disclosed. The system employs distributed caching techniques to assemble data objects at locations proximate to a source to avoid latency over delayed links. The assembled data objects are then multicast to one or more remote terminals in response to a request for the objects, thus reducing unnecessary data flow across the satellite link.

A method for time multiplexing subframes on a serving cell to a user equipment, wherein one set of subframes operate with the legacy LTE transmission format and one set of subframes operate with an evolved transmission format comprising reduced density CRS transmission without a PDCCH control region.

A gateway device configured to receive IP video content may select and use transmission methods that maintain a certain quality of service for delivering the content. A transmission method may be selected based on a network to which the client device is connected. The gateway device may select a network through which the content is to be delivered depending on a variety of factors including bandwidth availability, client compatibility, quality of service provided and the like. A gateway device may further be configured to convert multicast transmissions to unicast, to provide dynamic storage of content for pre-positioning and other purposes and/or to provide other functions.

A method and apparatus are described including multicasting a medium reservation message, receiving responses to the medium reservation message and determining if a ratio of the received responses to an expected number of responses exceeds a threshold. Also described are a method and apparatus including receiving a medium reservation message, determining if the medium reservation message specifies this receiver in a list of receivers from which a response is requested, determining if a medium is idle and transmitting the response to the medium reservation message responsive to the second determination.

A content distribution network with client side multicasting properties that operates with a reduced bandwidth is provided. The arequested content, such as multimedia content, is provided in a format suitable for transmission over existing unicast communication links and is then changed to a multicast format for local distribution. This allows an application provider to transmit a single unicast stream of content to a client-side media server in a local area network (LAN) and then distribute it to multiple interested users within the LAN using a multicasting transmission format. This significantly reduces bandwidth requirements by providing a single unicast transmission to a LAN rather than supply each user within the LAN with a dedicated content stream.

Methods and apparatus for implementing a robust unicast/broadcast/multicast protocol are provided. In one aspect, a method of avoiding collision of intra-basic service set unicast, broadcast or multicast transmissions notifies stations in the basic service set of a reserved transmit opportunity for a unicast, broadcast or multicast transmission. Transmissions from at least one station in the basic service set are deferred until after the reserved unicast, broadcast or multicast transmit opportunity.

In this invention, an idea of the reverse direction label switched path (RLP) in Multi-Protocol Label Switching (MPLS) is applied to the multicast transmission to improve the management transmission in the multicast transmission, and to easily carry out an additional connection and disconnection. Specifically, in the reverse direction symmetric routing Label switched Path (LP), a virtual label in addition to an input label and an output label is used for the reverse direction routing. However, in this invention, instead of the virtual label, a multicast address to which a client terminal, which is connected to a head of the path on the reverse direction routing, and corresponds to a leaf in the multicast tree, is connected, is registered, as a multicast index, in routers on the path. Then, when receiving a multicast packet including a label and a multicast address, an output label corresponding to the received label is identified, thereby a destination link is identified.

According to one embodiment of the invention, wireless spectrum and battery power conservation is achieved through an adaptable multicast group communication scheme. This involves a method for controlling the multicast transmission rate based on a first operation of receiving information from a multicast receiving device that is a member of a multicast group. Based on this information and potentially other information from other member devices, the modulation and coding rate for the multicast group is altered.

The invention relates to a mechanism for performing multicast transmission in a cellular network. In order to enable establishment of resources only in cells containing members of the multicast group and to avoid congestion on the uplink channel, a multicast service notification is transmitted to mobile stations, thereby informing members of the multicast group of an upcoming multicast session. The moment for a response to said multicast service notification is selected in the mobile stations and a presence report is sent from at least one of said mobile stations at the response moment of said at least one mobile station. The presence report or reports are received within a radio access network, and radio resources are established for multicast transmission in a cell of the cellular network when the presence report(s) received in said cell meet(s) predetermined criteria.

The invention discloses a pilot frequency transmission method for downlink shared multicast transmission, which is used in a long term evolution advance (LTE-A) system. The system is allocated with a plurality of sets of pilot frequencies for downlink multicast transmission and multiplexing modes thereof; and each transmission point involved in downlink share transmits one of the pilot frequencies in a resource block carrying user data, the same set of pilot frequency occupies the same time and frequency sites in the resource block, and the different sets of pilot frequencies are discriminated via frequency division, time division or code division in the resource block. The inventive method needs not a receiving terminal to discriminate channels corresponding to the transmission points which are involved in the share and only needs to allocate one set or a plurality of sets of logic pilot frequencies for multicast transmission, thereby resulting in low cost of pilot frequencies, simple terminal reception and less downlink control signaling.

A mechanism is provided in which multicast reverse path forwarding can be performed at a provider network egress edge router wherein core routers of the provider network are not configured to support multicast protocols or point-to-multipoint LSPs. An embodiment of the present invention provides for the creation of virtual interfaces in the egress edge router element during configuration of a multicast connection in response to a subscriber request. A virtual interface will be associated with an upstream ingress edge router element and that ingress edge router element is provided a label associated with the virtual interface. Such a label can then be included in datastream packets transmitted through the provider network. The label can then be used by reverse path forward checking at the egress edge router element to ascertain whether the multicast datastream is being received by the correct upstream interface (e.g., the virtual interface associated with the ingress edge router element). In such a manner, core network router elements of the provider's network need not be configured to process multicast transmissions as such, nor need the core router elements be configured to use the same network protocols as those used by the customer networks (e.g., customer networks can use IPv6 while the core network routers can use IPv4).

A method of and apparatus for providing an Internet Protocol multicast service wherein multicast data is transmitted through multicast routers (8) to user stations (9) over a digital broadcast channel (especially DVB-T) together with digital broadcast signals, at least if a request has been received from a user station (9) for the multicast data,. The transmission of the multicast data by a multicast router is conditional upon the reception of a request for said multicast data from that multicast router by a plurality of the user stations (9). The number of requests from the user stations (9) has to be greater than a threshold number, which is a function of the available bandwidth for multicast transmission over the broadcast channel. Information concerning the requests for the multicast data by the user stations (9) is unavailable to the other user stations (9).

Multiple paths in a communication network are provided between at least one source node and at least one destination node. The network arrangement may thus support either unicast transmission of data or multicast transmission. Measurements are made at nodes of the network to determine a partial network cost for data traversing the links in the multiple paths. An optimization procedure determines a distribution of the network traffic over the links between the at least one source node and the at least one destination node that incurs the minimum network cost.