New York University

Thanasis Korakis

Shivendra S Panwar

Elza Erkip

Pei Liu

Yao Rong Wang

Chun Nie

Salik Makda

Anna Scaglione

Ozgu Alay

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.

CoopMAX: a cooperative MAC with randomized distributed space time coding for an IEEE 802.16 network

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. 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.

Spatial multiplexing gain for a distributed cooperative communications system using randomized 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.

Cooperative MAC for rate adaptive randomized distributed space-time coding

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 determined. 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, a better measured wireless channel condition than that of receiver nodes assigned to the second group. At least some of the receiver nodes of the first group of nodes are selected to serve as relay nodes. Video information is then transmitted wirelessly from the video server node to the receiver nodes assigned to the first group. Each of the selected relay nodes then transmits at least a part of the video information to the receiver nodes of the second group.

Video multicast using relay devices defined by a channel quality parameter hierarchy

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.

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Brooklyn, NY, United States of America

Thanasis Korakis