Patent application number | Description | Published |
20080285480 | Cooperative Wireless Communications - When it is advantageous to do so, a wireless LAN station sends data packets to a destination station via an intermediate station, instead of to the destination station directly. That is, the intermediate station, which serves as a helper to the source, forwards packets received from the source station to the intended destination station. This cooperative data transmission approach can result in system performance improvement, as long as the total time consumed by two-hop transmission (i.e., transmission via the helper station) is less than direct transmission. Such a determination may be made using rate information stored at each station. Specifically, using the rate information, signaling needed to set up a transmission, the amount of data to be transmitted, etc., transmitting the data directly and via a help station may be compared. | 11-20-2008 |
20090034614 | FEEDBACK ASSISTED TRANSMISSION OF MULTIPLE DESCRIPTION, FORWARD ERROR CORRECTION CODED, STREAMS IN A PEER-TO-PEER VIDEO SYSTEM - MD-FEC is considered an efficient way to generate a large number of descriptions. However, typically, MD-FEC introduces significant redundancy across streams. MD-FEC encoded streams (descriptions) are adapted based on feedback. Specifically, the bits sent in each description by a supplying peer are adapted based on the number of available descriptions in its receiving peer. The adaptive delivery eliminates unnecessary bits in the original MD-FEC streams (descriptions), and significantly reduces the consumed uplink bandwidth at supplying peers. The saved bandwidth can be used to accommodate more video sessions or for other applications. | 02-05-2009 |
20090037968 | USING LAYERED MULTI-STREAM VIDEO CODING TO PROVIDE INCENTIVES IN P2P LIVE STREAMING - A distributed incentive mechanism is provided for peer-to-peer (P2P) streaming networks, such as mesh-pull P2P live streaming networks. Video (or audio) may be encoded into multiple sub-streams such as layered coding and multiple description coding. The system is heterogeneous with peers having different uplink bandwidths. Peers that upload more data (to a peer) receive more substreams (from that peer) and consequently better video quality. Unlike previous approaches in which each peer receives the same video quality no matter how much bandwidth it contributes to the system, differentiated video quality, commensurate with a peer's contribution to other peers, is provided, thereby discouraging free-riders. | 02-05-2009 |
20090122770 | SENDER AND/OR HELPER NODE MODIFICATIONS TO ENABLE SECURITY FEATURES IN COOPERATIVE WIRELESS COMMUNICATIONS - Wireless protocols that employ a helper node are adapted so that they may take advantage of authentication security (and perhaps encryption security). Thus, such protocols may be used with security protocols such as 802.11i protocol (or the like) for example. | 05-14-2009 |
20090147746 | VIDEO MULTICAST, SUCH AS LAYERED VIDEO MULTICAST FOR EXAMPLE, USING RELAY DEVICES DEFINED BY A CHANNEL QUALITY PARAMETER HIERARCHY - Improved distribution of video information in an infrastructure-based wireless network is provided. A wireless channel condition between the video server node and each of the plurality of receiver nodes is measured (or accepted, or otherwise determined). Each of the plurality of receiver nodes are assigned into one of a first group and a second group using the measured wireless channel conditions, wherein receiver nodes assigned to the first group have, on average (e.g., on average over time), a better measured wireless channel condition than that of receiver nodes assigned to the second group. At least some (e.g., one or more) of the receiver nodes of the first group of nodes are selected to serve as relay nodes. Video information (e.g., N layers) is then transmitted wirelessly from the video server node for reception by each of the receiver nodes assigned to the first group. Each of the selected relay nodes then transmit at least a part (e.g., M≦N layers) of the video information for reception by at least some of the receiver nodes of the second group such that the relay nodes collectively transmit the at least a part of the video information to all of the receiver nodes of the second group. Receiver nodes assigned to the first group receive, decode and render the received video information. Similarly, receiver nodes assigned to the second group, receive, decode and render the received at least a part of the video information. The receiver nodes assigned to the second group may also use the (1) video information transmitted wirelessly by the source node and/or (2) copies of the at least a part of the video information transmitted by other relay nodes (that is, relay nodes not assigned to it), to the extent such information is received. | 06-11-2009 |
20090316763 | SPATIAL MULTIPLEXING GAIN FOR A DISTRIBUTED COOPERATIVE COMMUNICATIONS SYSTEM USING RANDOMIZED CODING - Multiple cooperative relays operate in a highly mobile environment and form a virtual antenna array. Multiple independent streams of data can be simultaneously transmitted in parallel to the destination receiver. Thus a higher spatial multiplexing gain can be obtained. Such exemplary embodiments might do so by allowing each relay to transmit a linear combination of antenna waveforms according to an independently and randomly generated coefficient vector. This randomized cooperation scheme may be useful in an environment in which a group of relay devices are close to the source device, and can therefore receive information at a high rate. Each relay device that receives the information without errors splits it into multiple streams. For example, if the relay devices receive B symbols and the number of streams is K, each stream contains B/K symbols. Each relay device then generates a random linear combination of all the streams and transmits this output simultaneously with the other relay devices. | 12-24-2009 |
20100005185 | SUBSTREAM TRADING IN A PEER TO PEER LIVE STREAMING SYSTEM - In a live video P2P system using substream trading, a peer device's video quality is generally commensurate with its upload rate. Such substream trading provides in a P2P live video streaming system provides incentives and can accommodate a variety of video coding schemes. In particular, substream trading with layered video has many desirable properties, including differentiated service, short start-up delays, synergies across peer device types, and protection against free-riders. | 01-07-2010 |
20100014453 | COOPERATIVE MAC FOR RATE ADAPTIVE RANDOMIZED DISTRIBUTED SPACE-TIME CODING - Data is transmitted from a source wireless device to a destination wireless device by: (a) discovering node-to-node wireless channel conditions in a wireless network; (b) determining at least one of (A) wireless relay devices, (B) modulation schemes, and (C) transmission rates using the discovered node-to-node channel conditions; (c) signaling at least some of the determined information to the determined wireless relay devices; (d) receiving, with each of the wireless relay devices, a transmission of the data from the source wireless device; and (e) transmitting, with each of the wireless relay devices, a randomized, space-time encoded, part of the received data, to the destination device using the signaled at least some of the determined information | 01-21-2010 |
20100049867 | ON DEMAND PEER-TO-PEER VIDEO STREAMING WITH MULTIPLE DESCRIPTION CODING - A peer-to-peer novel video streaming scheme is described in which each peer stores and streams videos to the requesting client peers. Each video is encoded into multiple descriptions and each description is placed on a different node. If a serving peer disconnects in the middle of a streaming session, the system searches for a replacement peer that stores the same video description and has sufficient uplink bandwidth. Employing multiple description coding in a peer-to-peer based network improves the robustness of the distributed streaming content in the event a serving peer is lost. Video quality can be maintained in the presence of server peers being lost. The video codec design and network policies have a significant effect on the streamed video quality. The system performance generally improves as the number of descriptions M for the video increases, which implies that a higher video quality can be obtained with the same network loading. | 02-25-2010 |
20110110290 | ROBUST COOPERATIVE RELAYING IN A WIRELESS LAN: CROSS-LAYER DESIGN - A distributed and opportunistic medium access control (MAC) layer protocol for randomized distributed space-time coding (R-DSTC), which may be deployed in an IEEE 802.11 wireless local area network (WLAN), is described. Unlike other cooperative MAC designs, there is no need to predetermine, before packet transmission, which stations will serve as relays. Instead, the MAC layer protocol opportunistically recruits relay stations on the fly. Network capacity and delay performance is much better than legacy IEEE 802.11g network, and even cooperative forwarding using one relay station. Avoiding the need to collect the station-to-station channel statistics considerably reduces overhead otherwise required for channel measurement and signaling. | 05-12-2011 |
20110170558 | SCHEDULING, INCLUDING DISTRIBUTED SCHEDULING, FOR A BUFFERED CROSSBAR SWITCH - Scheduling methods and apparatus are provided for buffered crossbar switches with a crosspoint buffer size as small as one and no speedup. An exemplary distributed scheduling process achieves 100% throughput for any admissible Bernoulli arrival traffic. Simulation results also showed that this distributed scheduling process can provide very good delay performance for different traffic patterns. The simulation results also showed that packet delay is very weakly dependent on the switch size, which implies that the exemplary distributed scheduling process can scale with the number of switch ports. | 07-14-2011 |
20110216662 | COOPMAX: A COOPERATIVE MAC WITH RANDOMIZED DISTRIBUTED SPACE TIME CODING FOR AN IEEE 802.16 NETWORK - Cooperative communication is a technique that can be employed to meet the increased throughput needs of next generation WiMAX systems. In a cooperative scenario, multiple stations can jointly emulate the antenna elements of a multi-input multi-output system in a distributed fashion. A framework for a randomized distributed space-time coding (“R-DSTC”) technique in the emerging relay-assisted WiMAX network, and the development of a cooperative medium access control (“MAC”) layer protocol, called CoopMAX, for R-DSTC deployment in an IEEE 802.16 system, is described. The technique described couples the MAC layer with the physical (PHY) layer for performance optimization. The PHY layer yields significant diversity gain, while the MAC layer achieves a substantial end-to-end throughput gain. | 09-08-2011 |
20110243052 | DYNAMIC RATE AND FEC ADAPTATION FOR VIDEO MULTICAST IN MULTI-RATE WIRELESS NETWORKS - Video multicast over Wireless Local Area Networks (WLANs) faces many challenges due to varying channel conditions and limited bandwidth. A promising solution to this problem is the use of packet level Forward Error Correction (FEC) mechanisms. However, the adjustment of the FEC rate is not a trivial issue due to the dynamic wireless environment. This decision becomes more complicated if one considers the multi-rate capability of the existing wireless LAN technology. A novel method which dynamically adapts the transmission rate and FEC for video multicast over multi-rate wireless networks is described. In order to evaluate the system experimentally, a prototype using open source drivers and socket programming was implemented. Experimental results show that the proposed system significantly improves the multicast system performance. | 10-06-2011 |
20120128007 | DISTRIBUTED SCHEDULING FOR VARIABLE-SIZE PACKET SWITCHING SYSTEM - Scheduling methods and apparatus are provided for an input-queued switch. The exemplary distributed scheduling process achieves 100% throughput for any admissible Bernoulli arrival traffic. The exemplary distributed scheduling process includes scheduling variable size packets. The exemplary distributed scheduling process may be easily implemented with a low-rate control or by sacrificing the throughput by a small amount. Simulation results also showed that this distributed scheduling process can provide very good delay performance for different traffic patterns. The exemplary distributed scheduling process may therefore be a good candidate large-scale high-speed switching systems. | 05-24-2012 |
20120128354 | DISTRIBUTED SCHEDULING FOR AN OPTICAL SWITCH - Scheduling methods and apparatus for use with optical switches with hybrid architectures are provided. An exemplary distributed scheduling process achieves 100% throughput for any admissible Bernoulli arrival traffic. The exemplary distributed scheduling process may be easily adapted to work for any finite round trip time, without sacrificing any throughput. Simulation results also showed that this distributed scheduling process can provide very good delay performance for different traffic patterns and for different round trip times associated with current switches. | 05-24-2012 |