Optimizing Superframe of IEEE 802.15.6 for Enhancing Network Performance

Abstract

IEEE 802.15.6 is a low power sensor network which works in the close vicinity of human bodyand is termed as Wireless Body Area Network(WBAN). A WBAN connects autonomous nodes (sensors) that are placed on the body of a person. IEEE 802.15.6 is proposed standard for WBAN and its applications are increasing day by day. WBAN uses low power devices that have short communication range with small data rates. IEEE 802.15.6 superframe provides ease of access for different traffic prioritization. The superframe is divided into different phases so that nodes can communicate according to traffic types. IEEE 802.15.6 assigns fixed duty cycle to network devices using its superframe. Every superframe contains information of different phases including:two Exclusive Access Phases (EAP), two Random Access Phases (RAP), and Managed Access Phase (MAP). EAP is only used for emergency traffic, RAP is used for all kind of traffics and MAP is polling based. Since IEEE 802.15.6 proposes a fixed superframe structure therefore the boundaries of different access phases cannot be changed dynamically according to traffic or network requirements. To overcome this problem we propose a two new schemes: dynamic Packet Delivery Ratio (PDR) scheme and dynamic content aware scheme.In both the proposed schemes superframe can be adjusted dynamicallye, g., if there is no emergency traffic in EAP its time can be allocated to other traffics and if there is additional emergency traffic then the EAP time is increased. As a result, network performance is increased in terms of increased network throughput and decrease in latency of communication. Detailed simulation analysis using OPNET simulator concludes that proposed scheme is better than fixed superframe proposed by IEEE 802.15.6.