Evaluation of BER in Bluetooth Wireless Systems Disturbed by Radiated Noise from Spread Spectrum Clock Systems

Takahide MURAKAMI
Yasushi MATSUMOTO
Katsumi FUJII
Akira SUGIURA

Publication
IEICE TRANSACTIONS on Communications   Vol.E89-B    No.10    pp.2897-2904
Publication Date: 2006/10/01
Online ISSN: 1745-1345
DOI: 10.1093/ietcom/e89-b.10.2897
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Electromagnetic Compatibility(EMC)
Keyword: 
dithered clock oscillator (DCO),  electromagnetic interference (EMI),  spread spectrum clock (SSC),  wireless local area network (WLAN),  wireless personal area network (WPAN),  

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Summary: 
Frequency-modulated clock signals are widely used in personal computers to reduce the amplitude of the clock harmonic noise, as measured using an electromagnetic interference (EMI) test receiver. However, the power of the clock harmonics is not decreased with this technique called spread spectrum clocking (SSC). Hence, the impact of the harmonics of a frequency-modulated clock on the bit error rate (BER) and packet error rate (PER) of a Bluetooth system is theoretically analyzed. In addition, theoretical analysis covers the effectiveness of a frequency hopping spread spectrum (FH-SS) scheme and forward error correction (FEC) in mitigating the degradation in the BER and PER caused by clock harmonic interference. The results indicate that the BER and PER strongly depend on the modulating frequency and maximum frequency deviation of the clock harmonic. They also indicate that radiated clock harmonics may considerably degrade the BER and PER when a Bluetooth receiver is very close to a personal computer. Frequency modulating the clock harmonics slightly reduces the BER while it negligibly reduces the PER.