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In this paper, we consider secure transmission for the full duplex relay network. Aiming to improve the physical layer security, we propose a full duplex hybrid relaying-and-jamming (FDHRJ) scheme. In the FDHRJ scheme, we design a pre-coding matrix to form a jamming signal and let the relay simultaneously transmit both the desired signal and the jamming signal every slot. The destination can decode...
This paper investigates the secrecy performance of half-duplex relay networks. First, we establish a relay broadcasting wiretap channel model using a half-duplex relay with multiple antennas and derive the instantaneous secrecy capacity of this system. With convex optimization, the upper bound on the capacity region is provided. Second, we give the expression for the ergodic secrecy rate and analyze...
As everyone knows, the energy of signals diminishes with increasing distance, so users at the edge of hexagon cells have lower signal-to-noise ratio (SNR) than users at the center, which means they are more easily interfered by signals from other base stations. So we consider the application of relay to the cellular case to help users at the edge to eliminate interferences and obtain higher sum-rate...
A low-power energy harvesting system targeting to harvest several microwatts from vibration is presented in this paper. The system consists of a piezoelectric vibration energy harvester and a power condition circuit. The proposed circuit store energy by an integrated bimorph piezoelectric generator that extracts energy from ambient vibrations. The generator is fabricated using thick film printing...
Utilizing spatial dimensions to align interference, interference alignment (IA) techniques can greatly improve spatial multiplexing benefits in interference-limited multiple antenna systems. In this paper, we focus on the closed-form design of IA in the multi-cell multi-user interfering networks with a finite number of antennas at each node. To obtain the same degrees of freedom (DoF), existing IA...
With the rapid extention of the electric transmission network, the workload of the inspection of transmission lines increases dramatically[1]. Unmanned fixed-wings aircrafts (UFV), a kind of unmanned aerial vehicle (UAV), can be applied to transmission line inspection to improve the efficiency. This paper introduces and discusses the application of a UFA to transmission line inspection. The inspection...
This paper analyses and designs a kind of wireless power transmission system via coupled magnetic resonances. It introduces the wireless power transmission technology, and expounds the principle of coupled magnetic resonant wireless power transmission technology and its superiority. Then it analyzes the influence of the related parameters such as the transmission distance d and load resistance RL...
To access the batteries information in the process of charge and discharge in time, the article designed a monitoring system for the condition of storage batteries based on ZigBee. This approach used the chip of CC2430, which was integrated of AD converter, 8-bit strengthened MCU and wireless RF unit. The chip of CC2430 and the external circuits were made up the node of the star network. The temperature,...
This paper proposes a codebook-based precoding method for multiple-input multiple-output (MIMO) amplify-and-forward (AF) relaying system. The proposed codeword selection criterion is a distributed codeword selection criterion which allows base station and relay to choose optimal precoding matrix independently. Therefore the feedback delay is decreased. Based on the proposed criterion, we further develop...
We introduce the Egs mote platform based on the Cortex M3 microcontroller that focuses on medical sensing applications. Egs uses an Atmel SAM3U microcontroller that runs up to 96 MHz and has up to 52 KB of RAM and 256 KB of Flash. Egs combines this microcontroller with two radios (802.15.4 and Bluetooth), external flash, on board sensors, and a LCD touchscreen to enable a rich set of wireless sensing...
Emerging technologies have made low-power and low-cost wireless sensor networks feasible. This paper presents a hierarchical wireless sensor network for measuring soil parameters such as temperature and humidity. Specifically, we designed sensor nodes that are placed completely underground and are used to collect soil measurements. These nodes use their radios to deliver the collected measurements...
When developing gigabit speed communication systems, a lot of design and implementation challenges emerge. And prototype is important to assess the overall system performance and complexity trade-offs under real-world conditions. In this contribution, prototype design and implementation of a time division-fourth generation (TD-4G) system-time division duplex-gigabit speed (TDD-GBPS) demonstration...
This paper presents Customer Satisfaction (CS) based resource allocation strategy in orthogonal frequency-division multiplexing (OFDM) wireless system with multimedia traffic. The risk aversion utility functions are analyzed, based on which, the CS utility and the CS resource allocation strategy are proposed. Compared with the Proportional Fairness (PF) utility, the CS utility enables the system to...
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