@misc{oai:ir.soken.ac.jp:00003591,
 author = {NGUYEN, Kien and グエン, キエン and NGUYEN, Kien},
 month = {2016-02-17, 2016-02-17},
 note = {The past two decades have seen increasing interests in the field of wireless sensor networks
(WSNs), which have potential applications covering all aspects of the human life. The major
issue in WSNs is power conservation since wireless sensors are usually battery-powered.
In a typical sensor node, the wireless interface consumes the largest share of the power
budget. Hence, an energy efficient medium access control (MAC) protocol is vital. The MAC
protocol always adopts the duty cycling mechanism to reduce idle listening, which is the most
significant energy wastage. The mechanism, however, has negative effects on latency and
throughput performance. Meanwhile, an increasing number of prospective applications not
only imposes requirements on energy efficiency but also on other Quality of Services (QoS)
parameters. Therefore, it is great of importance to design new efficient MAC protocols,
which meet the energy efficiency and QoS requirements.
We first focus on designing energy efficient, low latency MAC protocols for low data rate
WSNs. The traditional approach is letting a duty cycling MAC protocol forward packets
via multiple hops in a cycle, i.e., the multi-hop MAC. However, the original multi-hop MAC
protocol incurs a large control overhead, and a so-called long listening period problem. We
propose a low latency, low control overhead MAC protocol (the LO-MAC), which overcomes
the mentioned disadvantages by exploiting the physical properties of wireless channel. LO-
MAC introduces a new traffic adaptive scheme based on carrier sensing characteristics. The
scheme effectively controls the length of listening period following the traffic load. Moreover,
LO-MAC takes full advantages of the broadcast nature and lets a packet containing diffierent
meanings during its transmission. Therefore, the number of transmitting packets and the
control overhead is significantly reduced.
Secondly, we introduce an approach in designing efficient MAC protocols for dynamic load
environments. We propose MAC2 protocol, a novel Multi-hop Adaptive MAC protocol with
packet Concatenation. MAC2 achieves a better performance than a state-of-the-art protocol
in terms of energy efficiency, low latency and high throughput. The proposed protocol
controls the adaptation to the traffic load by combining a signalling traffic adaptive scheme
and a demand wakeup manner. The scheme and the manner are based on a synchronization
process and a proportional mapping function, respectively. Besides that, the protocol has a
concatenation scheme, which concatenates several queued packets into a bigger one before
sending out of a node. The concatenation scheme reduces not only the control overhead but
also the average latency. Additionally, MAC2 is numerically optimized to achieve minimum
latency and guarantee no data transmission collision.
Finally, we also target the dynamic load environments, but take an asynchronous approach
of the efficient MAC design. We propose an Asynchronous MAC protocol with QoS awareness
(the AQ-MAC), which is energy efficient and provides different QoS levels to relevant types
of traffic. AQ-MAC achieves energy efficiency and collision avoidance by utilizing a receiver-
initiated transmission and the concatenation scheme derived from MAC2. Moreover, AQ-
MAC adopts the diffierentiate service (DiffServ) model to provide QoS. Data packets are
provided diffierent transmission strategies depending on their levels of importance., 総研大甲第1557号},
 title = {EFFICIENT MAC PROTOCOL DESIGN FOR WIRELESS SENSOR NETWORKS},
 year = {}
}