A Novel Method for Service Differentiation in IEEE 802.15.4 : Priority Jamming

IEEE 802.15.4 employs carrier sense multiple access with collision avoidance (CSMA/CA), which is known to have difficulty for supporting quality of service (QoS). In this paper, a new priority scheme called priority jamming (PJ) is proposed for service differentiation for IEEE 802.15.4. The main idea of the proposed scheme is deferring the low priority packet transmission for the high priority packet. Clear channel assessment of IEEE 802.15.4 is modified to support the proposed PJ. The efficiency of the proposed scheme is validated by comparing the delay, throughput, and energy-per-bit with those of standard CSMA/CA. Simulations results showed that PJ improves the delay and throughput simultaneously while maintaining marginal difference in energy efficiency

Resilient IEEE802.15.4MAC Protocol for Multi-Hop Mesh Wireless Sensor Network

The success of a modern power grid system is inevitably based on the integration of a smart data exchange amid several devices in power production, transportation, dispatching and loads. For large coverage data exhange, a distributed multi-hop mesh is structured from low voltage distribution boards to the substations. Thus, being cheap, less power intake, easy set-up and operating in a free licensed spectrum, ZigBee/IEEE802.15.4 makes the most suitable wireless protocol for communicating in power grid systems. Nevertheless, IEEE802.15.4MAC protocol lacks a mechanism to enable a multi-hop mesh network with efficient energy and quality of service (QoS). Hence, in this paper, a Multi-Hop Mesh IEEE802.15.4MAC protocol is designed for a large coverage data exchange. This developed model provides a resilient network with energy efficiency and QoS. Hence, the IEEE802.15.4 super_frame_standard_structure is modified by swapping the contention_free period (CFP) and contention_access_period (CAP) for time sensitive applications. For network resilience, a Reserved_Broadcast Duration_Slot (RB_DS) is introduced in the active super_frame standard_structure as beacon_offset reference time computation. Finally, for the network performance analysis, the developed Markov chain_Model with retry and saturated traffic regime without feedback is run on NS-2 simulator. Here, the hidden terminal problem is not considered since it is assumed that all nodes can "hear" each other. The simulation results are encouraging as the developed IEEE802.15.4MAC protocol is capable of improving the time delivery delay up to 35.7%

Optimization of IEEE 802.15.4 : overview, theoretical study and simulation

In this paper we study, through theoretical analysis and simulation, the impact of Beacon Order (BO) and Superframe Order (SO) parameters of IEEE 802.15.4 on the networks performance and we investigate their optimal values for different classes of traffic. The traffic is dimensioned according to the requirements of the CANet project in which a cane becomes a mean of communication and a surveillance system embedding several sensors to monitor the elderly health and environment(voice, pressure, temperature, etc.). The cane's sensors impose different QoS constraints. Depending on the expected throughput, a sensor's traffic will fall within one of three classes that we defined. Therefore, in order to ease the understanding of our optimization, we introduce a classification scheme which applies to the existing quality of service algorithms. We derive by theoretical study the optimal values of BO and SO that should be used to fit each traffic class QoS requirements and we validate our results by simulation