Research Projects

WiFlex: Multi-Channel Cooperative Protocols for Heterogeneous Wireless Devices (WiFlex)

Ji Woong Lee, Jeonghoon Mo, Tran Minh Trung, Jean Walrand and Hoi-Sheung Wilson So

National Science Foundation CNS-0435478 and KOSEF

In ISM bands, many wireless protocols proliferate such as 802.11, bluetooth, and ZigBee. However, these incompatible protocols create complex coexistence and connectivity problems. If the same trend continues, similar interference and performance problems will continue to exist in future unlicensed bands. As new unlicensed bands open up, one can take a different approach to spectrum sharing. Instead of proposing a new MAC protocol for each type of application, we propose a family of parameterized MAC protocols called WiFlex that can tailor to different application needs ranging from wireless sensors to media center. Yet, these protocols within this family are compatible with each other to allow communication and spectrum-sharing coodination among different types of devices. We envision this family to be based on an OFDM-like multichannel physical layer.

The contribution of this paper includes the discovery of an asynchronous split-phase protocol with dynamic priority support. This protocol enables powerful devices to achieve a high throughput and protects low power devices with urgent but only occasional transmissions. It is distributed and data collision-free. Moreover, it can support low delays for real time applications.

The performance of the protocols are evaluated using an extension of NS-2. The results demonstrate the coexistence of devices with disparate radio characteristics and the support of applications with different requirements with good performance.

[1]

J. Lee, J. Mo, T. M. Trung, J. Walrand, and W. So, "WiFlex: Multi-Channel Cooperative Protocols for Heterogeneous Wireless Devices," IEEE WCNC 2008.

[2]

J. Lee, J. Mo, T. M. Trung, J. Walrand, and W. So, "WiFlex: Multi-Channel Cooperative Protocols for Heterogeneous Wireless Devices," IEEE Transactions on Networking (under review)

More information: http://www.eecs.berkeley.edu/~wlr