Patent application number | Description | Published |
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 |
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 |