Efficient Channel Utilization Schemes for IEEE 802.11 DCF over MANET

Abstract

The MAC protocol of IEEE 802.11 reduces hidden terminal problem using the RTS/CTS handshaking mechanism. However, it lacks the ability to release or reallocate a channel that was reserved but not used. For Mobile Ad hoc NETworks (MANET), this often keeps the channel unnecessarily inaccessible, resulting in inefficient channel utilization. In this paper, we propose schemes for releasing and reallocating unused channels in MANET deployed over IEEE 802.11. We introduce a Network Allocation Vector (NAV) updating method that can improve the performance of the existing RTS Validation scheme and our proposed Extra Frame Transmission scheme. We then combine these schemes as a further improvement. Through simulations, done in different scenarios with varying networking load and node density, we were able to show that combining these schemes leads to a throughput improvement of up to 40%. In addition, our proposed mechanisms have no compatibility problems.