Optimal Guard-band-aware Channel Assignment with Bonding and Aggregation

Channel assignment mechanisms in dynamic spectrum access (DSA) networks are often designed without accounting for adjacent-channel interference (ACI) between different secondary users (SUs). To prevent such interference, guard-bands are needed between channels that are assigned to different SUs. However, introducing guard-bands restricts the spectrum efficiency. In this paper, we consider the problem of designing an ACI-aware channel assignment for DSA networks that maximizes the spectrum efficiency. First, we consider a single link. The optimal assignment that maximizes the spectrum efficiency is formulated as a subset sum problem (SSP). An exponential-time dynamic programming (DP) exact algorithm, along with polynomial-time greedy and εapproximate algorithms are proposed and compared. Next, a set of links is considered, and the optimal exponentialtime assignment that maximizes the network spectrum efficiency is derived. A distributed implementation of the jointly optimal channel assignment for multiple links is presented. This distributed solution is compared with the sequential assignment, in which channels are assigned to links sequentially. Index Terms Channel assignment, dynamic spectrum access, spectrum efficiency.