Adaptive channel bonding in multicarrier wireless networks

To support high data rate applications such as multimedia streaming, the ongoing standardization of the next generation Wi-Fi increases the channel bonding from 40 MHz in 802.11n to 80, and even 160 MHz under certain conditions in 802.11ac. However, inefficiency and unfairness issues arise when devices that use different channel widths coexist in a contention domain. A device with channel bonding has to wait until all bonded channels to be idle to commence a transmission while narrow channel interferers have more channel access opportunities. To address the inefficiency and unfairness issues in channel bonding, we propose an adaptive channel bonding (ACB) protocol in which a node is allowed to initiate a transmission as long as a narrow channel is available and gradually increase channel width during transmission whenever a new narrow channel becomes available. ACB aggregates all available narrow channels as one wide channel, removing the need of setting guard bands between contiguous narrow channels. A challenge in the design is the communication over uncertain channels. To enable fast spectrum agreement between transmitter and receiver, a partial spectrum correlation method is introduced. ACB also considers the severe contention in a wide band of spectrum. When new channels become available, multiple nodes may contend for them. A compound preamble is designed to make collisions detectable in the frequency domain and a parallel bitwise arbitration mechanism is introduced to quickly resolve the collisions in the time domain. We implemented and evaluated the ACB through the GNU Radio/USRP platform. Experimental results show that ACB can well address the inefficiency and unfairness issues caused by heterogeneous radio coexistence.