142 research outputs found
Energy-Efficient Resource Allocation for Device-to-Device Underlay Communication
Device-to-device (D2D) communication underlaying cellular networks is
expected to bring significant benefits for utilizing resources, improving user
throughput and extending battery life of user equipments. However, the
allocation of radio and power resources to D2D communication needs elaborate
coordination, as D2D communication can cause interference to cellular
communication. In this paper, we study joint channel and power allocation to
improve the energy efficiency of user equipments. To solve the problem
efficiently, we introduce an iterative combinatorial auction algorithm, where
the D2D users are considered as bidders that compete for channel resources, and
the cellular network is treated as the auctioneer. We also analyze important
properties of D2D underlay communication, and present numerical simulations to
verify the proposed algorithm.Comment: IEEE Transactions on Wireless Communication
Generation of the Complete Four-dimensional Bell Basis
The Bell basis is a distinctive set of maximally entangled two-particle
quantum states that forms the foundation for many quantum protocols such as
teleportation, dense coding and entanglement swapping. While the generation,
manipulation, and measurement of two-level quantum states is well understood,
the same is not true in higher dimensions. Here we present the experimental
generation of a complete set of Bell states in a four-dimensional Hilbert
space, comprising of 16 orthogonal entangled Bell-like states encoded in the
orbital angular momentum of photons. The states are created by the application
of generalized high-dimensional Pauli gates on an initial entangled state. Our
results pave the way for the application of high-dimensional quantum states in
complex quantum protocols such as quantum dense coding.Comment: 4 pages, 4 figure
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