Total Order Reliable Convergecast in WBAN

Abstract

This paper is the first extensive work on total order reliable convergecast in multi-hop Wireless Body Area Networks (WBAN). Convergecast is a many-to-one cooperative scheme where each node of the network transmits data towards the same sink. Our contribution is threefold. First, we stress existing WBAN convergecast strategies with respect to their capacity to be reliable and to ensure the total order delivery at sink. That is, packets sent in a specific order should be received in the same order by the sink. When stressed with transmission rates up to 500 packets per second the performances of these strategies decrease dramatically (more than 90% of packets lost). Secondly, we propose a new posture-centric model for WBAN. This model offers a good characterization of the path availability which is further used to fine tune the retransmission rate thresholds. Third, based on our model we propose a new mechanism for reliability and a new converge-cast strategy that outperforms WBAN dedicated strategies but also strategies adapted from DTN and WSN areas. Our extensive performance evaluations use essential parameters for WBAN: packet lost, total order reliability (messages sent in a specific order should be delivered in that specific order) and various human body postures. In particular, our strategy ensures zero packet order inversions for various transmission rates and mobility postures. Interestingly, our strategy respects this property without the need of additional energy-guzzler mechanisms.

BAN-GZKP: Optimal Zero Knowledge Proof Based Scheme for Wireless Body Area Networks

“…When focusing on the comparison between BANZKP and BAN-GZKP, we noticed that BAN-GZKP has higher ratio of reception, lower end-to-end delay and number of transmissions in all the postures except the number of transmissions in the Posture 6 Sleeping, see Figure 23, where BANZKP has fewer number of transmissions than BAN-GZKP. In Posture 6, links between the nearby nodes to the sink may have important channel attenuations due to the obstruction and reflection of human body when sleeping [27]. Links who are far away from the sink affected by lower attenuations comparing with links who are close to the sink.…”

“…The fast increase of end-to-end delay in case of original TreeBased strategy in postures 6 and 7 (see Figure 100 for example). That because the general networks links quality are not good in posture 6 and 7 [27], the number of the retransmissions in these two postures are important, which lead to important collisions and backoffs with the increase of the packets generation rate. In general, BAN-GZKP has the lower end-to-end delay and number of transmissions in all the postures.…”

“…A flawed link not only lead to a decrease of the ratio of packets reception, but also an important number of retransmissions: that consumes the networks resource. If flawed links appear at the edge of the networks, like in postures 1,2 and 7 (see [27]), a hop-by-hop BAN-GZKP will limit the waste of the local retransmissions. But if the flawed links appear close to the sink, like in postures 3, 5 and 6, the BAN-GZKP could waste an important number of transmissions, according to the analyze for strategy APAP and CTP.…”

“…We therefore consider as case study the convergecast problem where Data messages sent by source nodes are collected by a specific node in the network called sink. We enrich representative convergecast strategies specifically designed for multihop WBAN mentioned in [26] and [27] with BANZKP and BAN-GZKP schemes, respectively. Note that the original BANZKP scheme requires an end-to-end authentication where all the authentication messages are transparent to relay nodes.…”

“…• Tree-based Strategy: [27] pre-constructs seven Best-Path Trees for different human postures shown in Figure 3. Source nodes send messages through these paths to the sink.…”