A channel allocation algorithm for OSA-enabled IEEE 802.11 WLANs

Abstract

Abstract-Channel allocation problem is a major challenge in wireless local area networks (WLANs), especially in dense deployments of access points (APs) where congestion of the unlicensed spectrum bands (i.e., ISM bands) could undermine achieved network performance. This paper analyses the possibility to alleviate congestion of the ISM band by allowing some APs to use additional channels located in licensed bands in an opportunistic manner whenever licensee services (i.e., primary users) are not affected. Availability of these additional channels in licensed bands is assumed not to be the same for all the APs. Based on this assumption, we formulate the problem for the channel assignment as a Binary Linear Programming (BLP) problem, which allows us to obtain an optimal solution despite an elevated execution time. We also develop a heuristic method based on building a Minimum Spanning Tree (MST) graph attending to interference conditions that is able to find nearoptimal solutions with a shorter execution time. Results are provided to assess the benefits of such a proposal under different WLAN deployment situations and primary channel availability conditions.

Decentralized robust spectrum allocation for cognitive radio wireless mesh networks

“…In [21] an opportunistic spectrum assignment is proposed in order to alleviate congestion in a WLAN environment. The problem is formulated as a binary linear program, where they seek to minimize the number of assigned bands without exceeding a maximum interference threshold.…”

“…With this in mind, the natural question that arises is to what purpose this assignment should be performed [20]. In our particular context, examples include minimizing the number of licensed bands assigned [21] or maximizing the user's utility (as a function of the mean rate) [22] without exceeding a maximum interference threshold to other networks. However, in the context of a cognitive WMN, we argue that the most natural objective would be to provide a lower bound to the resulting throughput in each link.…”

AP Deployment Research Based on Physical Distance and Channel Isolation

“…First, it allocates channels randomly for the AP and then allocates deployment point for the new APs using the deployable positions and generate a not completely same allocation result to constitutes a population, and calculate the adaptability function value of each individual in the population, and the number of the iteration is initialized as 0. When the number of the iteration is smaller than the predefined maximum iteration number, calculating the selection probability according to (18), uses the Roulette method to select individual pair for hybrid processing, uses the Roulette method to select a single individual for mutation processing to get rid of individuals less adaptive individuals, and finally it refreshes the population and the number of iterations.…”

“…Aiming at AP channel interference problems, there have been some research results, most of which are mainly through the graph coloring [1], integer linear programming [2], and heuristic method [3] for allocating channels for APs in ISM (industrial, scientific, medical) band to make the whole interference minimum. Reference [4] uses the cognitive radio technology, combined with the service condition of the primary users' band, to allocate accessible primary users' channels for AP. However, the above algorithms improve the system throughput by minimizing interference, which neither considers the influence from different business on the throughput nor guarantees the quality of service (QoS) of the system.…”

Experimental evaluation of opportunistic access in shared contention-based channels

“…Consequently, the secondary network searches for a new channel to use [3]. There exist several ongoing efforts that incorporate opportunistic channel access into IEEE 802.11 devices [4], [5], [6], [7], [8], [9], [10]. Those studies mainly focus on sensing the spectrum holes (also referred to as white spaces) and the channel selection mechanism.…”