Queue-Sharing Multiple Access Protocol

Background

Medium Access Control (MAC) protocols determine how multiple devices share a single communication channel. This started from the ALOHA protocol and evolved to the Carrier Sense Multiple Access (CSMA) protocol used in WiFi. Protocols have been generally divided into contention-based methods like ALOHA and CSMA, which are simple but have collisions at high traffic loads, and contention-free methods like Time Division Multiple Access (TDMA), which offer high efficiency but require complex clock synchronization and inflexible time slotting. While distributed queuing concepts have been proposed to help bridge this gap (e.g., DQDB or DQRAP) they have traditionally relied on physical time slots, dual buses, or complex signaling that makes them less suitable for modern demands of wireless networks.

Technology Description

To help address these challenges in modernizing communications protocols, researchers at UC Santa Cruz (UCSC) have developed Queue-Sharing Multiple Access (QSMA; including KALOHA with Queue Sharing a.k.a. KALOHA-QS or QSMA with No Carrier Sensing a.k.a. QSMA-NCS) which introduces a virtual, collision-free transmission schedule that’s similar to TDMA but without requiring physical time slots, clock synchronization, or a central coordinator. UCSC’s QSMA enables high-efficiency and collision-free communications by maintaining a global distributed queue state entirely through small data fields (e.g., queue size, position, ack, next) piggybacked on standard data packets, allowing nodes to self-organize into a dynamic firing order. The QSMA protocol that can seamlessly operate with or without carrier sensing, effectively solving the "hidden node" and "long propagation delay" problems that plague current standards. KALOHA-QS is a specific embodiment of the QSMA protocol designed to operate without carrier sensing, effectively upgrading the traditional ALOHA protocol by adding the "distributed queue" mechanism.

Applications

• IoT / wireless sensor applications
• underwater and acoustic communication applications
• satellite and long-range telemetry applications

Features/Benefits

• Eliminates the need for network-wide clock synchronization and fixed time slots, reducing hardware cost and complexity for IoT devices.
• Carrier-sense independent operation means high-efficiency and collision-free communication even in deaf environments like underwater and long-range.
• Unlike TDMA there are no empty slots waiting for idle nodes, ensuring near 100% channel utilization.
• Removes overhead of separate control channels or request-to-send (RTS) handshakes, which increases effective data throughput for small-packet traffic.

Intellectual Property Information

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