The Impact of a Dedicated Sensing Engine on a SDR Implementation of the CSMA Protocol

The practical realization of Medium Access Control (MAC) protocols using inexpensive Software Defined Radio (SDR) equipment is a challenge due to high communication delays between the radio hardware and the host computer. These delays hinder the implementation of MAC protocols since some phases such as the Clear Channel Assessment (CCA) phase as well as the subsequent channel access phase are subject to strict temporal constraints. In this paper, we employ a dedicated spectrum sensing engine as a CCA agent to enhance the sensing capabilities of a pure software implementation of a Carrier Sense Multiple Access (CSMA) based MAC protocol. Different scenarios are used to evaluate the performance of this sensing engine and its impact on the CSMA based MAC protocol. The experiment results show that using a hardware-assisted CCA mechanism has a positive impact on the slot time parameter as well as on the frame error rate as compared to a pure software implementation.