CMD: A Multichannel Coordination Scheme for Emergency Message Dissemination in IEEE 1609.4

Table 1

Comparison of existing multichannel VANET schemes.

Scheme	Utilizes RSU for coordination?	Nodes hosting the coordination function	Switching times per coordinator
Pal et al. [3]	No	1	Y-1
Chantaraskul et al. [13]	No	1	Y-1
VCI: [5]	No	1	Y-1
AMAC: [4]	Yes	1	Y-1
Lee et al. [8]	No	1	Y-1
FM-MAC: [9]	Yes	1	Y-1
DA-MAC: [10]	Yes	1	Y-1
Li et al. [11]	Yes	1	Y-1
WSD: [6]	No	1	Y-1
SAEMD: [15]	No	1	Y-1
Proposed CMD	No	Y-1	1

Switching times refers to the number of times a coordinator node must switch to different SCHs to transmit a single emergency message until all SCHs receive the message.