Abstract-Supporting high throughput is an important challenge in multi-hop mesh networks. Popular wireless LAN standards, such as IEEE 802.11, provision for multiple channels. In this article, we consider the use of multiple wireless channels to improve network throughput. Commercially available wireless network interfaces can typically operate over only one channel at a time. Due to cost and complexity constraints, total number of interfaces at each host is expected to be fewer than the total channels available in the network. Under this scenario, several challenges need to be addressed before all the available channels can be fully utilized. In this article, we highlight the main challenges, and present two link-layer protocols for utilizing multiple channels. We also present a new abstraction layer that simplifies the implementation of new multi-channel protocols in existing operating systems. This article demonstrates the feasibility of utilizing multiple channels, even if each host has fewer interfaces than the number of available channels.

The use of multiple wireless channels has been advocated as one approach for enhancing network capacity. In many scenarios, hosts will be equipped with fewer radio interfaces than available channels. Under these scenarios, several protocols, which require interfaces to switch frequently, have been proposed. However, implementing protocols which require frequent interface switching in existing operating systems is non-trivial. In this paper, we identify the features needed in the operating system kernel for supporting frequent interface switching. We present a new channel abstraction module to support frequent interface switching. We identify modifications to interface device driver to reduce switching delay. The channel abstraction module, and an example multi-channel protocol that uses the module, have been implemented in a multi-channel multi-interface testbed. We also present results to quantify the overheads of frequent switching.

The use of multiple wireless channels has been advocated as one approach for enhancing network capacity. In many scenarios, hosts will be equipped with fewer radio interfaces than available channels. Under these scenarios, several protocols, which require interfaces to switch frequently, have been proposed. However, implementing protocols which require frequent interface switching in existing operating systems is non-trivial. In this paper, we identify the features needed in the operating system kernel for supporting frequent interface switching. We present a new channel abstraction module to support frequent interface switching. We identify modifications to interface device drivers to reduce switching delay. The channel abstraction module and an example multichannel protocol that uses the module have been implemented in a multichannel multi-interface testbed. Our implementation efforts are part of the Net-X project which is aimed at developing operating system support for exploiting various forms of diversity available in a wireless network in the form of multiple channels, interfaces, transmission rates, transmission power-levels, etc.