Book contents
- Frontmatter
- Contents
- Preface
- Abbreviations
- 1 Introduction
- 2 An overview of wireless communications
- 3 Channel and propagation
- 4 Cellular and multiple-user systems
- 5 Diversity
- 6 Channel estimation and equalization
- 7 Modulation and detection
- 8 Spread spectrum communications
- 9 Orthogonal frequency division multiplexing
- 10 Antennas
- 11 RF and microwave subsystems
- 12 A/D and D/A conversions
- 13 Signals and signal processing
- 14 Fundamentals of information theory
- 15 Channel coding
- 16 Source coding I: speech and audio coding
- 17 Source coding II: image and video coding
- 18 Multiple antennas: smart antenna systems
- 19 Multiple antennas: MIMO systems
- 20 Ultra wideband communications
- 21 Cognitive radios
- 22 Wireless ad hoc and sensor networks
- Appendix A The Q-function
- Appendix B Wirtinger calculus
- Index
11 - RF and microwave subsystems
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface
- Abbreviations
- 1 Introduction
- 2 An overview of wireless communications
- 3 Channel and propagation
- 4 Cellular and multiple-user systems
- 5 Diversity
- 6 Channel estimation and equalization
- 7 Modulation and detection
- 8 Spread spectrum communications
- 9 Orthogonal frequency division multiplexing
- 10 Antennas
- 11 RF and microwave subsystems
- 12 A/D and D/A conversions
- 13 Signals and signal processing
- 14 Fundamentals of information theory
- 15 Channel coding
- 16 Source coding I: speech and audio coding
- 17 Source coding II: image and video coding
- 18 Multiple antennas: smart antenna systems
- 19 Multiple antennas: MIMO systems
- 20 Ultra wideband communications
- 21 Cognitive radios
- 22 Wireless ad hoc and sensor networks
- Appendix A The Q-function
- Appendix B Wirtinger calculus
- Index
Summary
Introduction
The term microwaves is used to describe electromagnetic waves with frequencies from 300 MHz to 300 GHz, corresponding to wavelengths in free space from 1 m to 1 mm. Within the microwave range, from 30 GHz to 300 GHz the wavelengths are between 1 mm and 10 mm, and hence these waves are known as millimeter waves. Below 300 MHz the spectrum of electromagnetic waves is known as the radio frequency (RF) spectrum, while above the microwave spectrum are the infrared, visible optical, ultraviolet, and x-ray spectrums. Wireless communications uses only the electromagnetic waves in the range of the microwave and RF spectrums. In the wireless communications literature, the term RF is often used to represent the entire RF and microwave spectrums.
Receiver performance requirements
The requirements on RF receivers are typically more demanding than those on transmitters. In addition to the requirements on gain and noise figure, the receiver must have:
A good sensitivity to the minimum power at the antenna for a given BER requirement. For example, the GSM standard requires a reception dynamic range from −102 dBm to −15 dBm, IEEE 802.11g requires a reception range of −92 dBm to −20 dBm, for WCDMA it is −117 to −25 dBm (before spreading), for CDMA2000 it is −117 dBm to −30 dBm, and for WideMedia it is −80.8 dBm/MHz (or −72.4 dBm/MHz at highest speed) to -41.25 dBm/MHz. For multiple data rates, a higher data rate requires a higher sensitivity, since it requires a larger SNR.
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- Wireless Communication SystemsFrom RF Subsystems to 4G Enabling Technologies, pp. 373 - 463Publisher: Cambridge University PressPrint publication year: 2010
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