CU-MAC: A Duty-Cycle MAC Protocol for Internet of Things in Wireless Sensor Networks

Abstract

Nowadays “Internet of Things” or IoT becomes the most popular technology in the Internet system. Types of devices and sensors have been connected as a network of devices and sensors. While a wireless sensor network is a traditional network of sensors that can be considered as a beginning point of IoT systems. Currently, these sensor data are not only exchanged within a local network but also are delivered to other devices in the Internet. Consequently, well-known organizations such as IEEE, IETF, ITU-T and ISO/IET are trying to set standards for wireless sensor devices in IoT systems. The recommended standard utilizes many of internet stack standards such as CoAP, UDP and IP. However, the traditional design of WSNs is to avoid using internet protocol in the system to reduce transmission overhead and power consumption due to resource limitation. Fortunately, the current technology in both hardware and software allow the internet standard to sufficiently operate in a small sensor. In this paper, we propose a MAC protocol named CU-MAC to efficiently support IoT standard that need request-respond communication or bi-direction communication. CU-MAC uses multi-channel communication to perform continuous and bi-directional data transfer at low duty-cycle. It also has a mechanism to overcome the hidden terminal problem. We evaluated the performance of CU-MAC on both simulation and real testbed based on Contiki OS. The result shows that CU-MAC outperforms other existing MAC protocols in term of packet delivery ratio at 98.7% and requires lower duty-cycle than others to operate in the high traffic environment.

QoS Strategies for Wireless Multimedia Sensor Networks in the Context of IoT at the MAC Layer, Application Layer, and Cross-Layer Algorithms

“…In different duty-cycle schedules, channel usage is checked by the destination nodes; that is, if the preamble found is long, it will remain powered on until the destination address is obtained, and in case it is the target, it will either await sender's data or go to sleep. e protocol has lower latency than synchronous MAC protocols but has a problem of overhearing where the neighbor node gets lengthy preambles though not the intended receiver, hence wasting a lot of power in doing so [24]. It outperforms a number of protocols via reconfiguration, feedback, and bidirectional interfaces for upper layer services.…”

“…It employs a multichannel mechanism for constant bidirectional transmission of packets at low duty cycle to resolve hidden-terminal issues. According to Danmanee et al [24], CU-MAC is an SI-MAC protocol that is aimed at improving bandwidth of the channel by initiating connections and transmitting data through different channels using the multichannel approach.…”

“…CU-MAC can reduce power wastage by choosing to employ only a single channel for transmitting both control packets and data in case there is only one sender in the same region of coverage. It can further enable multiple transmissions through another usable channel if there are other sending nodes in this area [24]. e protocol has two phases: (i) advertising phase, in which a source node announces to neighbors before transmission, and (ii) data transfer phase which commences when the source node receives a Readyto-Receive Information packet from the destination node.…”

“…So, in the absence of traffic in the locality, the node simply does periodic listening and sleeping, and to eliminate collisions, transmissions are distributively synchronized using a reservation-based model in case there is a sender to transmit data. R-MAC differs from S-MAC in that it transmits data to a number of nodes using the sleep mode [24]. ere are 3 stages in this protocol: (i) latency detection, (ii) period announcement, and (iii) periodic operation, of which (i) and (ii) are for node synchronization and (iii) is for listen/sleep procedures.…”

“…(a) Propagation latency between the 2 nodes L � (I 1 − I 2 )/2. (b) us, propagation latency can be defined as "the interval from the time the first node sends the first bit of a packet to the time the second node receives the last bit of the packet" [24]. (ii) Period announcement phase: here, nodes choose their own random listen/sleep time and start time and broadcast these, and when packets are received, the node turns the received schedule into its own.…”