A QUANTUM MULTIPLE ACCESS COMMUNICATIONS SCHEME USING ORBITAL ANGULAR MOMENTUM

We propose a quantum multiple access communications scheme using Orbital Angular Momentum (OAM) sector states in the paper. In the scheme, each user has an individual modified Poincare Bloch sphere and encodes his information with his own corresponding sector OAM states. A prepared entangled photon pairs are separated at transmitter and receiver. At the transmitter, each user encodes his information with the sector OAM states on the photons and the superposition of the different sector OAM states is carried by the photons. Then the photons are transmitted through quantum noiseless channel to the receiver. At the receiver, each user could retrieve his information by coincidently measuring the transmitted photons with the receiver side photons which are modulated by a special prepared measurement basis. The theoretical analysis and the numerical simulations show that each user could get his information from the superposition state without error. It seems that this scheme provides a novel method for quantum multiple users communications.

ZTE Communications Special Issue on Multiple Access Techniques for 5G

5G mobile cellular networks are required to provide the significant increase in network throughput, cell-edge data rate, massive connectivity, superior spectrum efficiency, high energy efficiency and low latency, compared with the currently deploying long-term evolution （LTE） and LTE-advanced networks. To meet these challenges of 5G networks, innovative technologies on radio air-interface and radio access network （RAN） are important in PHY design. Recently,

ZTE Communications Special Issue on Multiple Access Techniques for 5G

5G mobile cellular networks are required to provide the significant increase in network throughput,cell-edge data rate,massive connectivity,superior spectrum efficiency,currently deploying long-term evolution(LTE)and LTE-advanced networks.To meet these challenges of 5G networks,

Visible light communication based on space-division multiple access optical beamforming

We propose and demonstrate a visible light communication （VLC） scheme based on space-division multiple access （SDMA） optical beamforming to accommodate multiple user devices in the VLC based on optical beamforming. SDMA optical bealnforming is a technique which separates light-emitting diode light spa- tially and focuses each part on different target devices simultaneously. We show the experimental results of the VLC signal amplitudes, the optical power densities, and the bit-error rate performance as a function of transmission distance before and after the SDMA optical beamforming. The results show that the VLC signal amplitudes and optical power densities are improved by 8-2 and 3.8- 5 dB, respectively, with the help of SDMA optical beamforming.

Exploiting the Cellular Infrastructure for Data Transmission in Smart Metering Systems

To implement the access and backhaul networks for Smart Metering (SM) systems various technologies are combined with the existing communications infrastructure. This paper deals with data transmission in SM systems, focusing on how the existing cellular networks infrastructure is employed to implement SM access communication networks. The analysis aims at analyzing the role of the cellular communications infrastructure taking into account the spatial distribution and installation points of the smart meters, the urban and topological characteristics of the SM deployment areas and the common practice so far followed by the utilities. It is demonstrated that cellular communications, either exclusively or combined with power line communications, enable immediate and scalable deployment of SM access communication networks at low installation cost, thus constituting the basic option for the implementation of smart metering.

Engineering costs proxy models for China rural access network and its application

The article builds three engineering rural access network models that describe the structure of network elements and their relative engineering parameters for cable access, synchronous code division multiple access（SCDMA）, and very small aperture terminal （VSAT） access technologies in the rural areas of China. Of the three access technologies, cable access and SCDMA access are the most popular access technologies. Besides, there still exist some remote special areas such as western mountain areas, whose natural environment is so bad that VSAT becomes the unique economical access way. Fully considering rural areas＇ geographical environments＇ impact, the article introduces geographical revised factor （GRF） to the models. By substituting the network data from the operators into the models, the article obtains the integrated networking values and does further researches on different access networks.