  This paper considers the problem of high dimensional signal detection in a
large distributed network whose nodes can collaborate with their one-hop
neighboring nodes (spatial collaboration). We assume that only a small subset
of nodes communicate with the Fusion Center (FC). We design optimal
collaboration strategies which are universal for a class of deterministic
signals. By establishing the equivalence between the collaboration strategy
design problem and sparse PCA, we solve the problem efficiently and evaluate
the impact of collaboration on detection performance.
