Packet Switching in Radio Channels: Part I--Carrier Sense Multiple-Access Modes and Their Throughput-Delay Characteristics

Abstract

Absfract-Radio communicationis considered as a method for providing remote terminal access to computers. Digital byte streams from each terminal are partitioned into packets (blocks) and transmitted in a burst mode over a shared radio channel. When many terminals operate in this fashion, transmissions may conflict with and destroy each other. A means for controlling this is for the terminal to sense the presence of other transmissions; this leads to a new method for multiplexing in a packet radio environment: carrier sense multiple access (CSMA). Two protocols are described for CSMA and their throughput-delay characteristics are given. These results show the large advantage CSMA provides as compared to the random ALOHA access modes.

Collision-Resolution Algorithms and Random-Access Communications

“…In either case, the transmitters can then abruptly terminate the otherwise unproductive slot. Such techniques are generally known as "carrier-sensing" [14], and we now analyze their effectiveness in conjunction with the Capetanakis collision-resolution algorithm (CCRA).…”

On multiple access random medium access control

“…Wit~~ut coordination, each user transmits at rate ' R1 WIth probability P and at rate R 2 with probability 1-p. When both users transmit at rate R 1, the rate pair is outside the capacity region (2). Thus, the receiver cannot decode both packets.…”

“…We could also choose R I =~log ( 1+ (k-I)P+CT 2 ) and WI =k, where k is an integer in {l, ... ,N}. The average throughput is 2009 where P is the probability of choosing R I .…”

“…The MAC layer is traditionally designed separately from the physical layer. Most conventional random access protocols such as Aloha [1] and carrier sense multiple access (CSMA) [2] assume simple collision models, where the channel is noiseless, and reception failure is caused by collisions among users. Though the analysis and protocol design are simple in the collision model, the maximum achievable throughput of this model is limited.…”

Design of High Capacity Wireless LANs based on 802.11b Technology

“…The hidden terminal problern occurs when two ( or more) stations outside the hearing range of each other transmit to the same station within the hearihg range of both, causing a collision. The presence of hidden terminals results in a significant loss of capacity [7,6,9].…”