Frequency Hopping Spread Spectrum: An Effective Way to Improve Wireless Communication Performance
نویسنده
چکیده
To improve the performance of short-range wireless communications, channel quality must be improved by avoiding interference and multi-path fading. Frequency hopping spread spectrum (FHSS) is a transmission technique where the carrier hops from frequency to frequency. For frequency hopping a mechanism must be designed so that the data can be transmitted in a clear channel and avoid congested channels. Adaptive frequency hopping is a system which is used to improve immunity toward frequency interference by avoiding using congested frequency channels in hopping sequence. Mathematical modelling is used to simulate and analyze the performance improvement by using frequency hopping spread spectrum with popular modulation schemes, and also the hopping channel situations are investigated. In this chapter the focus is to improve wireless communication performance by adaptive frequency hopping which is implemented by selecting sets of communication channels and adaptively hopping sender’s and receiver’s frequency channels and determining the channel numbers with less interference. Also the work investigates whether the selected channels are congested or clear then a list of good channels can be generated and in practice to use detected frequency channels as hopping sequence to improve the performance of communication and finally the quality of service. The Fourier transform mathematical modules are used to convert signals from time domain to frequency domain and vice versa. The mathematical modules are applied to represent the frequency and simulate them in MATLAB and as result the simulated spectrums are analysed. Then a simple two-state Gilbert-Elliot Channel Model (Gilbert, 1960; Elliott, 1963) in which a two-state Markov chain with states named “Good” and “Bad” is used to check if the channels are congested or clear in case of interference. Finally, a solution to improve the performance of wireless communications by choosing and using “Good” channels as the next frequency hopping sequence channel is proposed.
منابع مشابه
Performance Improvement of Wireless Communications Using Frequency Hopping Spread Spectrum
To improve the performance of short-range wireless communications, channel quality must be improved by avoiding interference and multi-path fading. Frequency hopping spread spectrum (FHSS) is a transmission technique where the carrier hops from frequency to frequency. For frequency hopping a mechanism must be designed so that the data can be transmitted in a clear channel and avoid congested ch...
متن کاملPLFC: the packet length fuzzy controller to improve the performance of WLAN under the interference of microwave oven
Abstrnct In this paper, we design a novel fuzzy controller to dynamically adjust the packet length to against the interference from microwave oven over the IEEE 802.11 FHSS (Frequency Hopping Spread Spectrum) wireless LAN card. The idea of adjusting the packet length under the noise environment is referring from the measurement results about the effects of microwave ovens over the wireless LAN ...
متن کاملBER Performance Analysis of Frequency-Hopping and Direct-Sequencing Spread Spectrum for Cognitive Radio Networks
Cognitive radio is an encouraging technology for future wireless communication networks. Due to the rapid increase in wireless services, the RF spectrum is going through a scarcity problem. This has forced mobile operators to participate in multimillion dollar auctions to reserve some spectrum resources. Cognitive radio tries to solve this scarcity problem by effectively using the unused portio...
متن کاملPerformance Analysis of Frequency Hopping Techniques in DBPSK Modulation System
With more and more developments in wireless communication, spread spectrum modulation techniques have been widely used in various modulation systems. Frequency hopping technique is one of the types of spread spectrum system. In this paper, frequency hopping techniques are compared in a DBPSK modulation system which employs non coherent reception. Fast frequency hopping and multicarrier frequenc...
متن کاملIntroduction of Frequency-Domain Signal Processing to Broadband Single-Carrier Transmissions in a Wireless Channel
Recently, frequency-domain equalization (FDE) has been attracting much attention as a way to improve single-carrier (SC) signal transmission in a frequency-selective wireless channel. Since the SC signal spectrum is spread over the entire signal bandwidth, FDE can take advantage of channel frequency-selectivity and achieve the frequency diversity gain. SC with FDE is a promising wireless signal...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2011