From least interference-cost paths to maximum (Concurrent) multiflow in MC-MR wireless networks
IEEE INFOCOM 2014 - IEEE Conference on Computer Communications
Maximum multiflow and maximum concurrent multiflow in multi-channel multi-radio (MC-MR) wireless networks have been well-studied in the literature. They are NP-hard even in single-channel single-radio (SC-SR) wireless networks when all nodes have uniform (and fixed) interference radii and the positions of all nodes are available. While they admit a polynomial-time approximation scheme (PTAS) when the number of channels is bounded by a constant, such PTAS is quite infeasible practically. Other
... ractically. Other than the PTAS, all other known approximation algorithms, in both SC-SR wireless networks and MC-MR wireless networks, resorted to solve a polynomial-sized linear program (LP) exactly. The scalability of their running time is fundamentally limited by the general-purposed LP solvers. In this paper, we first introduce the concept of interference costs and prices of a path and explore their relations with the maximum (concurrent) multiflow. Then we develop purely combinatorial approximation algorithms which compute a sequence of least interference-cost routing paths along which the flows are routed. These algorithms are faster and simpler, and achieve nearly the same approximation bounds known in the literature. IEEE one such that serves the cumulative link flow of Π. As fundamental problems in multihop wireless networking, both MMF and MCMF received much research interest in the past decade. Most of the existing studies (e.g., , , , , , ,  ) assumed some variants of the protocol (as opposed to physical) interference model. In general, a protocol interference model specifies a pairwise conflict relations among all links in , and a subset of is independent if its links are pairwise conflict-free. It is classified into two communication modes: • Unidirectional mode: For each link = ( , ) ∈ , the communication between and occurs in the direction from to , and the endpoint (respectively, ) is referred to as the sender (respectively, receiver) of . The sender of the link has an interference range, and the interference range of is the interference range of its sender. Two links in conflict with each other if and only if the receiver of at least one link lies in the interference range of the other link. • Bidirectional mode: For each link = ( , ) ∈ , the communication between and occurs in both directions, and both and have an interference range. The interference range of is the union of the interference ranges of its two endpoints. Two links in conflict with each other if and only if at least one link has an endpoint lying in the interference range of the other link.