XY-MAC: A short preamble MAC with sharpened pauses for wireless sensor networks

Abstract

Short preamble MAC protocols such as X-MAC use a series of consecutive short preamble packets with pauses between them, which refer to as a strobed preamble. Target receiver can send an ACK packet during those pauses to stop the preamble transmission. Hence, the average length of transmitted preamble is reduced in this way, higher energy efficiency and lower latency are achieved accordingly. But with pauses longer than the transmission of an ACK packet, the sampling period at receivers is increased significantly as well, which makes it suboptimal of energy efficiency in light traffic load networks. In this paper, the XY-MAC proposes a technique called early termination to sharpen the size of those pauses. With sharpened pauses, the sampling period at receivers can be effectively reduced to acquire a high level of energy efficiency, especially under low traffic loads. A set of experiments have been held to compare with X-MAC. The results show that the duty cycle can be reduced to 37% to 65% of X-MAC under various traffic loads and bit rates.