Trade-off Analysis of a MAC Protocol for Wireless e-Emergency Systems

Oscar Gama1, Paulo Carvalho1, J. A. Afonso2 and P. M. Mendes2

Universidade do Minho, Campus de Gualtar1
Departamento de Informática
P-4710-057 Braga, Portugal

E-mail: {osg,pmc} at

Universidade do Minho, Campus de Azurém2
Departamento de Electrónica Industrial
P-4800-058 Guimarães, Portugal

E-mail: {jose.afonso,paulo.mendes} at


Wireless sensor networks are envisioned to be deployed in healthcare. Since emergency and intensive care applications need to assure reliable and timely data delivery, they have increased demands for quality of service, including at the MAC layer. Amongst MAC protocols available for WSNs, the Low Power Real Time (LPRT) presents suitable characteristics to be deployed in emergency platforms due to its rational bandwidth allocation, low energy consumption, and bounded latency. Yet, this protocol may present a significant packet loss ratio in a wireless channel with bit error ratio. In order to define a MAC protocol more robust to bit error conditions and able to fulfill the required quality of service, solutions based on short size beacons and multiple retransmissions are proposed and tested. The results showed that such strategies led to meaningful improvements regarding packet loss ratio, without compromising significantly the energy consumption.

S-Cube 2009, Pisa, Italy, September 7-9, 2009