tailieunhanh - Lecture Wireless and mobile computing – Chapter 22: Spread spectrum (Review/Recap)

The following will be discussed in this chapter: Relationship between bandwidth of a signal (before and after and encoding SS), benefits of SS, FHSS, slow and fast FHSS, DSSS, relationship between bit rate of a signal (before and after DSSS encoding), CDMA. | Spread Spectrum Review/Recap Lecture 22 Overview Relationship between bandwidth of a signal (before and after and encoding SS) Benefits of SS FHSS Slow and Fast FHSS DSSS Relationship between Bit Rate of a Signal (Before and after DSSS encoding) CDMA Bandwidth Before and After SS Encoding Q:- What is the relationship between the bandwidth of a signal before and after it has been encoded using spread spectrum? Definition of Spread Spectrum Spread spectrum is a modulation method applied to digitally modulated signals that increases the transmit signal bandwidth to a value much larger than is needed to transmit the underlying information bits. Spread Spectrum Signal Characteristics They are difficult to intercept for unauthorized person. They are easily hidden, it is difficult to even detect their presence in many cases. They are resistant to jamming. They have an asynchronous multiple-access capability. They provide a measure of immunity to distortion due to multipath propagation. Spread Spectrum Conditions The signal occupies a bandwidth much larger than is needed for the information signal. The spread spectrum modulation is done using a spreading code, which is independent of the data in the signal. Despreading at the receiver is done by correlating the received signal with a synchronized copy of the spreading code. Processing Gain : The spread spectrum increases the bandwidth of the message signal by a factor N, called the processing gain where β is the message signal bandwidth, βss is the corresponding SS signal bandwidth. , N > 1 Spread Spectrum Versus Narrowband Technology Narrowband wireless communications can be defined as wireless communications using a single frequency center with no redundancy to communicate information at high power levels chosen to overpower interference in that frequency band. Spread spectrum wireless communications can be defined as wireless communications using a range of frequencies to communicate | Spread Spectrum Review/Recap Lecture 22 Overview Relationship between bandwidth of a signal (before and after and encoding SS) Benefits of SS FHSS Slow and Fast FHSS DSSS Relationship between Bit Rate of a Signal (Before and after DSSS encoding) CDMA Bandwidth Before and After SS Encoding Q:- What is the relationship between the bandwidth of a signal before and after it has been encoded using spread spectrum? Definition of Spread Spectrum Spread spectrum is a modulation method applied to digitally modulated signals that increases the transmit signal bandwidth to a value much larger than is needed to transmit the underlying information bits. Spread Spectrum Signal Characteristics They are difficult to intercept for unauthorized person. They are easily hidden, it is difficult to even detect their presence in many cases. They are resistant to jamming. They have an asynchronous multiple-access capability. They provide a measure of immunity to distortion due to multipath .

• Quản trị mạng
• Mobile computing simulations
• Network simulation
• Mobile computing
• Wireless and mobile computing
• Services data
• Wireless communication
• Mobile AD hoc networking
• Data dissemination
• Opportunistic networks
• Task farming in crowd computing
• Mobility models
• Simulations in VANET
• Wireless Communications Principles
• Modern Wireless Communication Systems
• Wireless Technologies
• Wireless Personal Area Networks
• Bluetooth Personal Area networks
• Wireless local area networks
• Lecture Wireless networks
• Wireless networks
• Bài giảng Mạng không dây
• Introduction to Wireless communication
• Wireless transmission
• Digital data analog signals
• Wireless Communications Principles and Practice
• Introduction to Wireless Communication Systems
• Components of score
• Modulation Techniques for Mobile Radio
• Wireless Networking
• Multiple Access Techniques for Wireless
• Wireless transmission media
• Wireless propagation modes
• Communication networks
• Modern cellular standards
• Differential encoding
• Virtual circuit
• International Journal of Computer Networks and Communications Security
• Inter cluster communication in wireless sensor networks
• Wireless sensor networks
• Inter cluster communication
• Carrying out efficient diffusion
• Cluster merging and cluster diffusion
• Planar quasi yagi for next generation wireless communication systems
• Planar quasi yagi
• Next generation wireless communication systems
• End fire radiation pattern
• Achieve optimal model
• Wireless LAN technology
• International journal of computer science & communication networks
• Survey on applications of wireless sensor network in industries
• Challenges of wireless sensor network in industries
• Wireless sensor network in industries
• Wireless sensor network
• Wireless Communications
• Wireless communications technology
• Technological development
• Wireless Communication Systems
• Mobile Radio Commnunication
• Wireless communications methods
• The Wireless vision
• Radio waves
• Channel capacity
• Signal to noise ratio
• Evolution of wireless networks
• Packet switched network
• Global information multimedia communication village
• Wireless mesh networks
• Multipoint to multipoint communication
• Increases network capacity
• Highly dynamic topology
• Communication paradigm
• Managing inventory control
• Error control
• Digital communication system
• Microstrip planar antenna
• 5G wireless applications
• Omnidirectional pattern
• Reflection coefficient
• 5G wireless communication applications
• Adaptive data rate
• Energy efficient
• Long range wireless communication
• Energy efficiency approach