Combinatorics

Physics

Channel (broadcasting)

Topology (electrical circuits)

Relay

Computer network

Mathematics

Relay channel

Wireless

Algorithm

Mathematical optimization

Optimization problem

Power (physics)

Outage probability

Computer science

Quantum mechanics

Fading

Telecommunications

IEEE Transactions on Wireless Communications

Optimal relay placement is studied for free-space optical multihop communication with link obstacles and infeasible regions. An optimal relay placement scheme is proposed to achieve the lowest outage probability, enable the links to bypass obstacles of various geometric shapes, and place the relay nodes in specified available regions. When the number of relay nodes is large, the searching space can grow exponentially, and thus, a grouping optimization technique is proposed to reduce the searching time. We numerically demonstrate that the grouping optimization can provide suboptimal solutions close to the optimal solutions, but the average searching time linearly grows with the number of relay nodes. Two useful theorems are presented to reveal insights into the optimal relay locations. Simulation results show that our proposed optimization framework can effectively provide desirable solution to the problem of optimal relay nodes placement.

Relay Placement for FSO Multihop DF Systems With Link Obstacles and Infeasible Regions