Block acknowledgment mechanisms for the optimization of channel use in wireless sensor networks

Abstract

One of the fundamental reasons for the IEEE 802.15.4 standard Medium Access Control (MAC) inefficiency is overhead. The current paper proposes and analyses the Sensor Block Acknowledgment MAC (SBACK-MAC) protocol, a new innovative protocol that allows the aggregation of several acknowledgment responses in one special BACK Response packet. Two different solutions are addressed. The first one considers the SBACK-MAC protocol in the presence of BACK Request (concatenation) while the second one considers the SBACK-MAC in the absence of BACK Request (piggyback). The proposed solutions address a distributed scenario with single-destination and single-rate frame aggregation. The throughput and delay performance is mathematically derived under ideal conditions (a channel environment with no transmission errors). The proposed schemes are compared against the basic access mode of IEEE 802.15.4 through extensive simulations by employing the OM-NET++ simulator. We demonstrate that the network performance is significantly improved in terms of throughput and end-to-end delay.

Block acknowledgment in IEEE 802.15.4 by employing DSSS and CSS PHY layers

“…In Section III we provide an accurate analytical model for the throughput and end-to-end delay limits by considering our proposed BACK mechanism for both the cases of implementing or not BACK Request. Section IV provides both numerical and simulation results and extends our earlier work in [6] In our previous work in [6], we have shown that one of fundamental reasons for the IEEE 802.15.4 standard MAC inefficiency is overhead, and we have proposed a mathematical model that derives the throughput and end-to-end delay limits under ideal conditions (a channel environment without transmission errors). In the scope of our current research, we study the impact on the performance of the CSS and DSSS PHY layers and we also carry out a comparison against the IEEE 802.15.4 standard.…”

“…Like in [6], we analyse the maximum throughput, S max , and the minimum delay, D min , for the IEEE 802.15.4 DSSS and CSS PHY layers. S max is defined as the number of data bits generated from the MAC layer that can be transmitted per second to its destination including the ACK reception.…”

Performance enhancement of IEEE 802.15.4 by employing RTS/CTS and frame concatenation

“…repetition of the backoff phase and IFS. Hence, although RTXs are an important source of overhead, the issue can be mitigated by using efficient RTX mechanisms. In [22], we have proposed a mathematical model that derives the throughput and end‐to‐end delay limits under ideal conditions (a channel environment with no transmission errors). In the scope of this research, we address both the best‐case scenario, where no transmission errors exist, and the more realistic case that considers transmission errors, which originates frame RTXs.…”

“…Consequently, the transmitter randomly selects a uniformly distributed backoff time period, in the range . It is worthwhile to mention that, even if there is only one transmitter and one receiver, the transmitter will always choose a random backoff period within , which causes delay, as defined in [22]. Before starting a new transmission, each device sets initially the BE equal to macMinBE .…”

“…Table 2 presents the key parameters, and defines symbols and values for the DSSS PHY, previously utilised in [12], that will be considered throughout this work. Detailed definitions are given in [22]. Table 3 [12] presents a comparison between the DSSS and CSS PHY layers.…”