An upper bound on bit error rate for a single user of a two-user system as a function of the interfering user's signal strength

Author(s):  
S. Sud ◽  
B.-P. Paris
Author(s):  
Richard Sowles ◽  
Derek Suen ◽  
David Loker ◽  
John T. Roth

Wireless sensors used in plant floor environments have been studied for obstruction and multipath propagation effects on signal quality. The trend towards wireless industrial data networks motivates this study, which explores the use of IEEE 802.15.1 radios in a machine shop at varying levels of operation. Previous studies have investigated the use of a wireless sensor embedded in a rotating tool holder to monitor tool life. In order to obtain information furthering the potential use of low power radio in conjunction with machining enclosures, a Bluegiga WT12 Class 2 Bluetooth 2.1 module is placed within several CNC machining enclosures at varying table positions and heights. An exterior module receives the data from the enclosed unit, and the module’s position is also varied in 3 dimensional space. Bit Error Rate and Received Signal Strength are measured, and the effects of spatial obstruction and multipath propagation are analyzed. An Agilent 8563E spectrum analyzer equipped with an Aaronia HyperLOG 7060 EMC antenna is also used to repeat the measurements at all of the points in order to provide EMI channel characterization and a redundant source of signal power data for comparison. Large-area transmissibility testing indicates that received signal strength is not dependent upon equipment operation. The enclosure tests (perimeter, height, and proximity comparison) suggest that distance, both static and transient path obstructions, multipath propagation, and line-of-sight are factors that influence bit error rate and received signal strength. Spectrum analyzer measurements in our shop show no significant emissions in the 2.4 GHz range that cause interference. At no time during this study did the bit error rate reach 0.2% of the transmitted bits and there were no failures in transmitting text between modules. Overall, the findings indicate that reliable data transmission with low power off-the-shelf Bluetooth modules is feasible.


Author(s):  
Hakeem Sanya Bolarinwa

This work investigated the quality of signal strength coverage of the existing Digital Terrestrial Television (DTTV) operator in Nigeria using Startimes Ibadan as a case study. Signal strength and altitude data at different locations within a 40km radius of the Startimes transmitting station were measured to determine the quality of signal strength reception of Startime's digital television in Ibadan metropolis. A signal analyzer, a 10-meter cable, Yaggi external antenna and Global Positioning System (GPS) were used for the measurements at various locations in Ibadan within 40km radius distance of Startimes based station at Agodi in Ibadan. The city was grouped into six different zones for proper signal testing and efficient data collation. Parameters such as signal strength, distance, altitude, signal to noise ratio, modulation error rate, pre-bit error rate and post-bit-error rate were measured and recorded. The effects of distance and altitude were analyzed. It was observed from the result that there is a direct relationship between power level and altitude. In addition, there is an inverse relationship between power level and distance.


2011 ◽  
Vol E94-B (5) ◽  
pp. 1438-1441
Author(s):  
Hyun-Seok RYU ◽  
Jun-Seok LEE ◽  
Chung-Gu KANG

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