BACKGROUND

Medium-access control (MAC) protocols based on collision avoidance have become increasingly important over the past few years due to their simple applicability to wireless local-access networks (LANs) and ad-hoc networks. In traditional collision-avoidance protocols, the transmitting node first sends a request-to-send (RTS) packet to the receiver, which, if it receives this RTS correctly, responds with a clear-to-send (CTS) signal. In this system, a sender can transmit a data packet only after successfully receiving a CTS. However, to prevent data packets from colliding with other packets at the intended receivers in networks with a single channel, the senders must sense the channel before sending the RTS. This carrier sensing or assignment of unique codes to nodes ensures that the intended receivers hear data packets without interference from hidden sources. However, this can limit the applicability of these systems because the senders and receivers must find each other's codes before communicating with one another.

DESCRIPTION

Scientists at the University of California have developed a novel group of MAC protocols called receiver-initiated channel-hopping (RICH) protocols. These are the first MAC protocols based on receiver-initiated collision-avoidance handshakes that provide collision-free reception of data at the intended receivers in the presence of hidden terminals without the need for carrier sensing or unique code assignments to nodes.

APPLICATIONS

This new invention has applications in ad-hoc networks based on commercial radios operating in unlicensed frequency bands.

ADVANTAGES

The new UC technology provides the following benefits:

• Solves the hidden-terminal problem by eliminating data packet collisions without the need to carrier sensing or code assignments;
• System performance does not depend upon the network topology.

REFER ALSO TO UC CASES 2000-303, 2000-311, 2000-349 THROUGH 356, 2000-360, 2000-380, 2000-383 THROUGH 385

Patent Status

Country	Type	Number	Dated	Case
United States Of America	Issued Patent	7,002,910	02/21/2006	2000-314

Inventors

• Garcia-Luna-Aceves, Jose Joaquin(JJ
• Tzamaloukas, Asimakis

Other Information

Contact

University of California, Santa Cruz Office for Management of Intellectual Property / technology@ucsc.edu / tel: View Phone Number. Please reference Tech ID #10183.

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ADDITIONAL TECHNOLOGIES BY THESE INVENTORS

• Scalable Integrated Services Architecture For Computer Networks
• Multicast Routing Protocol For Wireless And Mobile Computer Networks
• Bandwidth Efficient Source Tracing (Best) For Wireless Networks
• On-Demand Loop-Free Multipath Routing
• Differentiating Congestion Vs. Random Loss: A Method For Improving Tcp Performance Over Wireless Links
• Improving Tcp Congestion Control Over Internets With Heterogeneous Transmission Media
• Mpath: A Loop-Free Multipath Routing Algorithm Using Predecessor Information
• Receiver Initiated Multiple Access For Ad-Hoc Networks
• Group Coordination Protocol For Networked Multimedia Systems
• System And Method For Ad Hoc Network Access Employing The Distributed Election Of A Shared Transmission Schedule
• Tree-Based Ordered Multicasting