方法对比

	载波侦听多路访问/冲突避免 (CSMA/CA)	多输入多输出 (MIMO)	Slotted ALOHA 随机接入协议
领域	电信	电信	电信
方法族	Process / pipeline	Process / pipeline	Process / pipeline
起源年份	1990	1995	1970
提出者	Phil Karn	Telatar, Foschini, and Gans	Norman Abramson and Lawrence Roberts
类型	random access protocol	spatial multiplexing technique	random access protocol
开创性文献	Karn, P. (1990). MACA—a new channel access method for packet radio. In Proceedings of the ARRL/CRRL Amateur Radio 9th Computer Networking Conference, 134-140.	Telatar, I. (1999). Capacity of multi-antenna Gaussian channels. European Transactions on Telecommunications, 10(6), 585-595.	Roberts, L. G. (1975). ALOHA packet system with and without slots and capture. ACM SIGCOMM Computer Communication Review, 5(2), 28-42.
别名	medium access control, WiFi MAC	spatial multiplexing, antenna diversity	random access, medium access
相关	3	5	3
摘要	CSMA/CA is a random access protocol for wireless medium access control, designed to enable multiple devices to share a wireless channel while minimizing collisions. Introduced by Phil Karn in 1990, it is the foundation of WiFi (IEEE 802.11) and is now the de facto standard for unlicensed spectrum access. CSMA/CA combines carrier sensing (listen before transmit) with collision avoidance (RTS/CTS handshake) to improve channel efficiency and fairness, avoiding the efficiency loss of pure random access (Aloha).	MIMO is a technique that uses multiple transmit and receive antennas to significantly increase channel capacity and reliability. Pioneered theoretically by Telatar (1999) and Foschini & Gans (1998), MIMO exploits multipath propagation—typically a liability in wireless—as an asset by creating independent spatial channels. It is now fundamental to all modern wireless systems including LTE, WiFi-6, and 5G, where it provides both capacity gains through spatial multiplexing and robustness through diversity.	Slotted ALOHA is a fundamental random access protocol enabling multiple devices to share a wireless channel without centralized coordination. Introduced by Abramson (1970) and refined by Roberts (1975), it divides time into fixed slots and allows devices to transmit at the beginning of a slot with a fixed probability. While simple and elegant, Slotted ALOHA achieves only 37% channel utilization under saturation (optimal traffic load), a fundamental limit discovered by Abramson. Despite this limitation, Slotted ALOHA remains a teaching tool and appears in modern systems like satellite and IoT networks.