Spatial Link Scheduling for SCDMA Multihop Cellular Networks: A Cross Layer Framework

Probability of error based Spatial Code Division Multiple Access scheduling algorithm is presented in this paper to systematically reuse the orthogonal CDMA codes in a given cell for Multihop Cellular Network. We assign and reuse the CDMA codes to peer-to-peer links such that the probability of error in all scheduled links are below certain threshold. The proposed scheduling algorithm PoE-LinkSchedule involves two phases. In the first phase we present a scheduling metric “Probability of Error (PoE)” as a function of first and second order statistics of wireless channel coefficients between nodes. The second phase presents a graph theoretical as well as PoE based centralized scheduling algorithm. For a graph of network with n number of nodes, U number of links and θ thickness, the proposed scheduling algorithm has computational complexity of O(Unlogn + Unθ) as opposed to O(UU ) in the case of exhaustive search algorithm. The performance of the proposed algorithm is evaluated in terms of spatial reuse and end-to-end throughput. We show that the proposed algorithm has considerably higher end-to-end throughput and higher spatial reuse compared to existing link scheduling algorithms.