Preliminary Project Proposal

IEEE 802.11n is a newly emerging wireless standard which, relative to former 802.11 protocols, such as 802.11a/b/g, has a number of new mechanisms that enable multifold increases in transmission speeds. These new mechanisms include multipleinput-multiple-output (MIMO) transmission schemes as well as the option for channel bonding two 20MHz channels into a single 40MHz channel. Furthermore, 802.11n has the option of operating in the 5GHz range, which offers a larger number of subchannels to operate on in comparison to operating in the 2.4GHz range, as is the case for 802.11b/g. Although 802.11n can potentially attain high data rates, given the number and complexity of features available in 802.11n, high data rates can only be achieved through intelligent channel management strategies. Channel management strategies are methods of combining the transmission characteristics of a wireless channel so as to achieve a certain level of communication performance. For example, in 802.11n, by considering the effects of MIMO, channel bonding, and DFS together on channel performance, we are not only dealing with a channel assignment problem, where channels are assigned to particular users, but rather a management problem where all the wireless characteristics should be addressed together to achieve a combined level of performance. Intelligent channel management strategies will consider efficient methods of exploiting the transmission characteristics; these strategies will ensure that a group of access points (APs), with their respective conflict graph (CG), are assigned channels so as to maximize channel reuse and minimize interference, i.e. to improve efficiency. Current research in wireless 802.11n technologies has mainly focused on link adaptation schemes[1]. In particular, research efforts have tried to understand and improve how 802.11n’s spatial dimension, introduced by MIMO, can be coupled with modulation and coding mechanisms to improve data rate. Therefore, it is clear that there has been little to no work on channel management in 802.11n wireless technologies. Channel assignment schemes for wireless resources are NPhard, graph-coloring, problems that have been addressed in the context of 802.11a/b/g technologies[2]. Existing channel assignment schemes attempt to allocate orthogonal channels to nodes that interfere with each other. A simple technique is to use static channel assignment. Although most existing solutions are static, recent work has addressed more dynamic channel assignment solutions whereby changes in network characteristics, such as load or interference, trigger channel reassignments [3], [2], [4]. For dynamic solutions, however, the question remains about when reallocation will be performed. In conclusion, although a considerable amount of work has considered heuristics[5] to solve the channel assignment problem, there is a limitation to the existing solutions if we are to apply them to 802.11n wireless technologies since the existing solutions are not able to utilize and benefit from the channel options that are available over 802.11n. The existing solutions do not exploit the flexibility and opportunities that 802.11n provides, particularly in the case of channel reassignments. Due to the number of features available in 802.11n, there is a need to develop a comprehensive channel management strategy that can address each feature available in 802.11n wireless technologies so as to maximize gains in channel capacity. Given the apparent gap in channel management solutions for 802.11n wireless technologies, there is a need for research which addresses the key features in 802.11n technologies and how they will influence channel management schemes. Such knowledge is important because it will help us exploit 802.11n’s ability to attain high data rates. However, before that, it would be helpful to motivate this need by providing intuitive results, as described in greater detail in the following section.