Channel Assignment for Maximum Throughput in Multi-Channel Access Point Networks

Abstract

Abstract-We consider the uplink channel assignment problem in a multi-channel access point wireless network, with the goal of attaining maximum system throughput. In this setup, a set of orthogonal channels must be assigned to a set of users, where each user splits its power optimally across the channels allocated to it. While the optimal power allocation solution has a "water-filling" type structure, the optimal channel assignment problem is very challenging due to the non-linear dependence of user throughput on the set of channels assigned to it. Since the optimal channel allocations is computationally intensive to obtain in general, we analyze the system in the two extremal SINR regimes (very high and very low SINR) and show how the optimal solutions can be obtained in these regimes in a computationally efficient manner. Finally, we demonstrate that the best of the optimal solutions obtained for the two extremes show excellent (close to optimal) performance over the entire SINR range.

Dynamic channel assignment and power allocation in multichannel wireless networks with per-user bandwidth guarantees

“…One of the main distinguishing aspects of our work from this existing body of work is our stochastic control/optimization based approach; in contrast, these existing works address related problems from a static optimization perspective. The questions that we address are closely related to our previous work [8], albeit in a deterministic setting. The consideration of time-varying arrivals and channel conditions, and the peruser minimum bandwidth guarantee requirements, make the problem in this paper much more complex than the "static" resource allocation question addressed in [8].…”

“…The questions that we address are closely related to our previous work [8], albeit in a deterministic setting. The consideration of time-varying arrivals and channel conditions, and the peruser minimum bandwidth guarantee requirements, make the problem in this paper much more complex than the "static" resource allocation question addressed in [8].…”

“…For multichannel OFDMA systems, there has been a significant amount of recent work addressing the channel assignment and power control problems [7], [2], [3], [5], [6], [12], [8]. One of the main distinguishing aspects of our work from this existing body of work is our stochastic control/optimization based approach; in contrast, these existing works address related problems from a static optimization perspective.…”

“…Here, ( ) corresponds to the real packet queue, as evident from the update equation (8). ( ) is a virtual token queue, that is maintained for each user (and updated according to (9)): it is needed by the algorithm, as described below.…”

“…Once ( ) has been determined, we update the virtual (token) queue according to (9). The real queue corresponds to the actual packet queue, so it gets updated according to (8) automatically, as packets arrive at and depart from the queue.…”