A Novel Packets Transmission Scheme Based on Software Defined Open Wireless Platform

The IEEE 802.11-2012, known as wireless-fidelity, offers a rich set of physical layer (PHY) features supported by advanced media access control (MAC) mechanisms. The use of off-the-shelf commercial 802.11 network interface card based (NIC-based) platforms constitutes an inexpensive prototyping approach based on reprogramming the cards software drivers. Besides, the commercial 802.11 NIC-based platform performs the functions of the MAC layer and PHY layer, respectively, by way of the firmware in the networking card and the software-driver running on the host computer, the former of which carries out the time-critical functions (Low MAC and PHY) while the latter serves the time-tolerant functions (High MAC). However, the maintenance of the cards produced in this way turns out quite troublesome. Therefore, based on a mixed real-time software-hardware architecture, i.e., a software defined open wireless platform, a novel packets transmission scheme is proposed in this paper in order to overcome the limitations of the NIC-based platform so that it becomes fully flexible and re-configurable. Furthermore, the novel scheme consists of three parts. First, a preliminary scheme is designed as follows: shift the hard-coded Low MAC and the PHY to the user space, then carry out the High MAC in the kernel space, and then combine the High MAC with the Low MAC via the Netlink. Second, based on preliminary scheme, the sending packets (i.e., the MAC frame) are reorganized in a lightweight way and the packets’ completeness and correctness are validated with experiments. Third, an M/M/1 model is exploited to create a packets transmission ring for optimizing the preliminary scheme. And the experimental results of the packets transmission concerned have proved the above-mentioned novel scheme outperforms the traditional one (i.e., the NIC-based platform) in terms of the system overhead and the number of packets sent in unit time.