Coding-aware MAC: Providing channel access priority for network coding with reverse direction DCF in IEEE 802.11-based wireless networks

Abstract

An important challenge for the implementation of network coding in IEEE 802.11-based wireless networks is to give additional priority for channel access to the relay stations responsible for coding. These relay stations are able to provide more information in a single transmission than those that forward single packets, hence improving throughput and energy efficiency. The Distributed Coordination Function (DCF) of the IEEE 802.11 standard is a contention-based Medium Access Control (MAC) protocol that provides an equal distribution of channel access opportunities for all competing stations. However, the relay station represents a congestion point and additional transmission slots should be assigned to it to increase the overall network performance. To address this issue we investigate a coding-aware MAC protocol, called Reverse Direction DCF (RD-DCF), which enables bidirectional communications between the relay station and another station with a single channel access invocation. This simple and backwards compatible mechanism allows the relay station to transmit a coded packet together with the acknowledgement immediately after receiving a data packet. The simulation results show a gain of up to 130% in terms of both throughput and energy efficiency for RD-DCF with network coding when compared to DCF.

Analysis of a network coding-aware MAC protocol for IEEE 802.11 wireless networks with Reverse Direction transmissions

“…RD-DCF+NC [10] exploits NC based on COPE with an enhanced access mechanism using RD-DCF. As shown in Figs.…”

“…Hence, N transmission slots are required to exchange N data packets from end to end. The maximum throughput of RD-DCF+NC is expressed by (10). …”

“…RD-DCF guarantees a balanced share of the channel for a relay node with respect to the rest of nodes in its coverage area by allowing it to transmit data when it receives data. In [10], we extended the operation of RD-DCF to fully exploit NC by allowing a relay node to transmit a coded packet immediately after receiving a data packet. We evaluated the performance of RD-DCF with NC in the Alice-and-Bob scenario and showed around 20% and 130% gains when compared to DCF with NC and standard DCF, respectively.…”

Reverse direction transmissions and network coding for energy-efficient Wi-Fi networks

“…In our previous work [8], we presented a new NC-aware MAC protocol, coined BidCode, that allows bidirectional transmissions involving network coded data packets between wireless nodes. BidCode is an extension of our previously proposed Bidirectional MAC (BidMAC) [9], [10] inspired by the already standardized Reverse Direction Protocol (RDP).…”

“…The performance evaluation of BidCode [8] was based on computer-based simulations considering the Alice and Bob scenario. In [11], we analyzed the upper bounds of BidCode throughput and energy efficiency in both the Alice and Bob and cross scenarios and produced performance evaluation using numerical results only.…”