In order to improve the spectral efficiency in wireless communications, multiple antennas are employed at both transmitter and receiver sides, where the resulting system is referred to as the multiple-input multiple-output (MIMO) system. In MIMO systems, it is usually requiredto detect signals jointly as multiple signals are transmitted through multiple signal paths between the transmitter and the receiver. This joint detection becomes the MIMO detection.
標簽： Complexity Detection MIMO Low
上傳時間： 2020-05-27
上傳用戶：shancjb
Nature is seldom kind. One of the most appealing uses for radio- telephone systems—communication with people on the move—must over- come radio transmission problems so difficult they challenge the imagina- tion. A microwave radio signal transmitted between a fixed base station and a moving vehicle in a typical urban environment exhibits extreme variations in both amplitude and apparent frequency.
標簽： Communications Microwave Mobile
上傳時間： 2020-05-28
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Software Radio (SR) is one of the most important emerging technologies for the future of wireless communication services. By moving radio functionality into software, it promises to give flexible radio systems that are multi-service, multi- standard, multi-band, reconfigurable and reprogrammable by software. Today’s radios are matched to a particular class of signals that are well defined bytheircarrierfrequencies,modulationformatsandbandwidths.Aradiotransmitter today can only up convert signals with well-defined bandwidths over defined center frequencies, while, on the other side of the communication chain, a radio receiver can only down convert well-defined signal bandwidths, transmitted over specified carrier frequencies.
上傳時間： 2020-06-01
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Second-generation telecommunication systems, such as the Global System for Mobile Communications (GSM), enabled voice traffic to go wireless: the number of mobile phones exceeds the number of landline phones and the mobile phone penetration is approaching 100% in several markets. The data-handling capabilities of second-generation systems are limited, however, and third-generation systems are needed to provide the high bit-rate services that enable high-quality images and video to be transmitted and received, and to provide access to the Web with higher data rates.
標簽： Evolution WCDMA UMTS HSPA LTE for and
上傳時間： 2020-06-01
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n the first part of this book, we give an introduction to the basic applications of wireless com- munications, as well as the technical problems inherent in this communication paradigm. After a brief history of wireless, Chapter 1 describes the different types of wireless services, and works out their fundamental differences. The subsequent Section 1.3 looks at the same problem from a different angle: what data rates, ranges, etc., occur in practical systems, and especially, what combination of performance measures are demanded (e.g., what data rates need to be transmitted over short distances; what data rates are required over long distances?) Chapter 2 then describes the technical challenges of communicating without wires, putting special emphasis on fading and co-channel interference. Chapter 3 describes the most elementary problem of designing a wireless system, namely to set up a link budget in either a noise-limited or an interference-limited system. After studying this part of the book, the reader should have an overview of different types of wireless services, and understand the technical challenges involved in each of them. The solutions to those challenges are described in the later parts of this book.
標簽： Communications Wireless Edition 2nd
上傳時間： 2020-06-01
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