A framework to support real-time applications over IEEE802.15.4 DSME

Abstract

IEEE 802.15.4e has specified Deterministic and Synchronous Multichannel Extension (DSME) mode that helps to support real-time applications over wireless mesh networks. It supports a multi-superframe structure where each superframe during a beacon interval can potentially be assigned to a coordinating (or routing) device. Each superframe supports Contention Free Period (CFP) and Contention Access Period (CAP). IoT devices that send periodic data may want to use CFP while devices that send aperiodic data may want to use CAP (or need some dynamic way of using CFP for the period when such devices are sending data). In certain types of surveillance use cases, IoT devices may send low amount of data in normal scenarios (such as temperature reading, low resolution images or video) but these devices may start sending high volume of delay-sensitive data upon detection of certain types of events. For example, several video surveillance cameras may be activated upon detection of movement of people in an area. We need mechanisms that allow tradeoff between diverse needs of aperiodic and periodic IoT applications while at the same time, we need to be able to meet QoS requirements of delay-sensitive and other applications. A flexible resource management framework is proposed in this paper to achieve these goals. As packets move from an originating device to a destination (or coordinator) device in upward direction, various types of compensation parameters are computed and conveyed as part of MAC packets. The receiving (or coordinator) node uses these parameters to compute a compensation factor and conveys that to originating device in downward direction via protocols such as Constrained Application Protocol. This compensation factor is also carried in MAC packets along with other parameters in the upward direction. Intermediate nodes use compensation factor to do dynamic management of resources in DSME networks. It allows flexible resource management to meet requirements of diverse types of IoT applications in DSME networks.