Design of the Software for Wirelessly Intercepting Voices

Transcription

1 Advanced Materials Research Online: ISSN: , Vols , pp doi: / Trans Tech Publications, Switzerland Design of the Software for Wirelessly Intercepting Voices Xiuchun He 1,a, Jun Liu 1,b, Jiahua Xie 1,c, Renqiu Chen 1,d 1 Engineering University of armed police force, Xi an , China a @qq.com, b @qq.com, c @qq.com, d @qq.com Keywords: zigbee technology, Voice intercepting, Design of the Software Abstract. Voice intercepting is an important method of the national security sectors to obtain criminal intelligence. This approach is secret, mandatory, statutory, and technical and commits a violation of privacy. The recent years of technical advancement enable criminals to adopt more sophisticated anti-investigation tools and thus impose stricter requirements on energy consumption and environmental adaptation of the intercepting systems. Zigbee is an emerging two-way wireless communication technology characterized by low power consumption, high capacity, low costs, short delays and great reliability. Hence, it is particularly suitable for automatic and remote control and can be built into any devices. Introduction The proposed voice incepting system is based on Zigbee and adopts the design strategy that combines modularity and hierarchy. It is greatly covert and can transmit across a long distance. The proposed system consists of terminal nodes, aggregating nodes and upper computers. Hardware Design The overall structure of the proposed system is shown in Fig.1. Fig.1. Overall structure of the proposed system The terminal nodes of the proposed system will collect the voice signals near the sound sources, perform A/D conversion, filtering and encoding on the collected signals, encapsulate the signals based on specified protocols and then send to the aggregating nodes via routes of the self-organized network. The data will be aggregated at the aggregating nodes and the useful information will be sent to the upper computers via UDP serial ports. After the reception of the data, the upper computers will decapsulate and analyze the data, extract voice signals and then store into local disks. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-08/04/16,22:21:43)

2 Advanced Materials Research Vols Software Design Software development platform. The proposed system is developed using IAR Embedded Workbench for MCS-51 from IAR Systems. The CC2530 module is used [4]. The embedded applications are compiled and configured using the assembly language, C and C++. Many operations, such as project management, compiling, connecting, downloading and error correction, can be performed on 8051 core-based processors. The terminal and aggregating nodes communicate using CC2530 s built-in IEEE (Zigbee) protocols. The aggregating nodes are connected to upper computers via UDP ports based on TCP/IP. Software design of the terminal node module. The terminal nodes of the proposed system are designed to collect, pre-process, encode and transmit signals. The workflows are shown in Fig.2. The terminal nodes have to operate robustly and reliably at the expense of fewer energy consumptions, because they are installed near the intercepted objects making it hard to repair or replace the power supplies. Hence, the terminal node software should be developed using simple statements to reduce workloads and lengthen battery life. Bugs must be eliminated from the statements to improve node reliability and robustness. In our system, the filtered voices are encoded using adaptive differential pulse code modulation (ADPCM). We can achieve the quality of voices at 32kb/s that is possible with pulse code modulation (PCM) at 64kb/s, with reduced complexity and greater error rate tolerance. Fig.2. Software workflows of terminal nodes Fig.3. Software workflows of aggregating nodes Software design of aggregating nodes. The aggregating nodes plays the role of a bridge in the system overall, aggregating and fusing the data from terminal nodes before sending the data to upper computers via UDP serial ports. The software workflows are shown in Fig.3. The adaptive weighted data fusion algorithm is adopted to eliminate redundant information, enormously reduce uncertainties and noises from collected data, lower the amount of data that needs to be transmitted across network nodes, and cut down energy consumption. Thus, it is essential to guarantee the working life of our system and the quality of the intercepted signals.

3 2472 Progress in Applied Sciences, Engineering and Technology Software Design of the upper computer module. The upper computer of the proposed system is responsible for final processing, decoding, replay and storage of the collected voice signals. It consists of verification module, configuration module, playback module, storage module and state module, as shown in Fig.4. Fig.4. Block diagram of the upper computer software The verification module is designed to ensure that the system is used validly. The configuration module can set up parameters about the system s work states, IP address of the destination, port of the destination and local storage site to ensure network connectivity. The replay module can restore digital signals to analog signals for replay or intuitively show the received voice signals in the form of waveforms. By using the storage module, we can compress the voice signals that need to be stored into local PC disks. The state module enables us to understand the system s working states by checking network connectivity, data receive rate, the number of online nodes, and the intensity of node signals.the software workflows are shown in Fig.5. Performance Evaluation The accuracy of voice collection is assessed in terms of signal restoration and noise elimination. In our tests, we choose one male and one female volunteers to say Hello to the terminal nodes and the microphones of the upper computer, respectively. Adobe Audition is used to compare the replay of the voice waveforms from the upper computer with the waveforms of the voice signals collected on-site. The test results are shown in Fig.6. From the results, we can see that the voice signals collected by the proposed system are almost the same as the original signals. Hence, it is able to collect, transmit and replay the voice signals. The design objectives are fulfilled. Summary The software design of the wireless intercepting system is analyzed overall. The software design workflows of each module are detailed. The software performance is tested. Results show that the proposed system is able to collect, transmit and replay the voice signals. Our system can also be set up easily and used reliably. The design objectives are fulfilled.

4 Advanced Materials Research Vols Fig.5. Software workflows of the upper computer On-site waveform of the female signals Replay waveform of the female signals On-site waveform of the male signals Replay waveform of the male signals References [1] Wang Xinglong.Design and Implementation of Voice Senor Nodes [D].Nanjing:Nanjing University of Posts and Telecommunications,2011. [2] ZhouJie. Digital Wireless Voice Transmission System based on TDD[D]. Chengdu: Southwest Jiaotong University,2005. [3] Jongseo Sohn,Wongyong Sung.A Voice Activity Detector Employing Soft Decision Based Noise Spectrum Adaptation, Proceeding of the IEEE Speech Coding Workshop,1998, [4] LiuJun, Zhang Jinbang, Yu Xiangzhen, et al. Design of pulse apperceive node based on CC2530 [J]. Application of Electronic Technique, 2013, 01: [5] Peng Lihua. Voice Activity Detection Techniques in High-noise Environments [D]. Wuhan: Huazhong University of Science and Technology, 2007.

5 Progress in Applied Sciences, Engineering and Technology / Design of the Software for Wirelessly Intercepting Voices /