ofdm modulation

across the coverage area. B) The user accesses WLAN from time to time. For example, the person attending the meeting needs to check the email from time to time during the meeting. The first requirement requires Seamless Roaming Across the WLAN. WLAN to meet this requirement should increase the access point density. The second requirement is an intermittent wireless connection. The access point density can be relatively small. 2.2 AP coverage The RF signal propagation principle of WLAN: the lowe

modulation system that uses a single-carrier Wavelet transform. SLC (Simple Line Code) is a baseband signaling version that filters the baseband and restores it at the transceiver. VDSL uses frequency division multiplexing (OFDM) to separate channels. In the future, VDSL will support symmetric data rates, which may need to be switched to feedback suppression. Generally, the downstream channel is configured

transceiver, equivalent to the wireless hub. )The ISM band does not need to apply for frequency-consuming bands;OFDM Orthogonal Frequency Division MultiplexingCSMA/CA Carrier Listen multiple access/collision avoidance (MAC layer access control)DSSS Direct sequence spread spectrum modulation technologyCCK Complementary key control technologyPBCC packet binary convolution technologyDBPSK Differential Two p

frames in the CTS can work at the same rate. Frames sent to a particular workstation will be recorded at address 1 for a single point of communication. A single-point propagation frame (Unicast frame) can be delivered at any rate supported by the destination. As for the choice of data rate, the 802.11 standard is not regulated. An acknowledgment frame such as an ACK or CTS must be transmitted at a rate that is included in the base rate combination, but not higher than the starting frame

is no error, the control information is removed and sent to the Data Link Layer LLC sublayer.6.WiMAX and OMA, TR069From the protocol stack defined by the three, WiMAX focuses on the bottom part of the protocol, which is closely related to the wireless network equipment, that is to solve the problem of how to send data and receive data by wireless network equipment. The protocol stack for OMA and TR069 is defined in the Transport layer (TCP or WDP), the session layer (HTTP or WSP), the presentat

Transferred from: http://baike.baidu.com/link?url= KEOJCOEXYDZUH8N7BNUGEDUTAGLDGDI7ESJUSZESPUREBK0NI6SFMTPWGIRED-H-L3ZZ7CY6QSHXVHHILK7BCQ the speed at which a microcontroller or computer communicates at the serial port. Refers to the signal is modulated after the change in the unit time, that is, the number of times the carrier parameter changes in the unit time, such as 240 characters per second, and each character format contains 10 bits (a starting bit, 1 stop bit, 8 data bits), the baud rate

Some key LTE technologies in Vernacular I have never been in touch with the actual LTE equipment because I am working on CDMA, but I have read a lot of theoretical materials, including the red books. I personally feel that Chinese books are not very good yet, it covers a wide range of topics, but there are very few details. If you want to study it in depth, unless you look at the agreement, but how tired the agreement looks, not like the books of previous motorcycles and Ericsson, the knowledge

Figure 8-4-3 of the voltage controlled oscillator, this characteristic describes the oscillation frequency ω U of the voltage controlled oscillator. Take ω 0 Center, UC with input signal voltage (T) changes. The expression for this feature is (8-4-6) When UC (T) The oscillation frequency ω U of the voltage controlled oscillator varies with time It also changes with time. The phase-locked loop enters the "Frequency traction" and automatically tracks and captures the frequency of the input signa

there are tags nearby. RFID is usually called a near-pairing system for communication at a very close distance. The range of near-pairing systems is usually 0 to 1 cm. This means that the tag is appended to the reader or pressed to the reader. The advantage of this close distance is that the label battery plant can produce a lot of energy. This energy is sufficient to support tag communication without the need for Built-in power. Near-matching is also conducive to highly confidential occasions.

------------------------------------------------------------------------------- Chorus reverbParameter value range descriptionMod. freq0.8hz0.1-20Hz Modulation SpeedMod. depth40 % 0-100% modulation depthMod. dly1.3ms0-24ms delay time before initiation of modulationRev. time2.4s0.3-30s reverb timeHigh ratio0.70.1-1 high-frequency attenuation rateDiffusion70-10 reverb DiffusionDelay Time between ini. dly30ms

the data is represented by binary or more discrete level values. Therefore, the communication channel maximum transmission rate and channel bandwidth have a clear relationship, so people can use "bandwidth" to replace the "rate." For example, people often use the network's "high data rate" to express the "high bandwidth" of the network. So "bandwidth" and "rate" are almost synonymous in the discussion of network technology. ------------------------------------------------------ bit rate. Baud

attenuation rateDiffusion60-10 reverb DiffusionThe delay time between INI. dly12.0ms0.1-200.0ms and early reflection.Cut-off frequency of lpf4.0khz1.0khz-16108khz.thru low-pass filterCut-off frequency of hpfthruthru, 32hz-8khz high-pass filter Reverb vocal used for voice and chorus reverbParameter value range descriptionRev. time1.9s0.3-30.0s reverb timeHigh ratio0.50.1-1.0 high-frequency attenuation rateDiffusion60-10 reverb DiffusionDelay Time between INI. dly16ms0.1-200.0ms direct and earl

WiMAX Overview World wide (WiMax) is a wireless transmission technology based on the IEEE 802.16 standard. As the "last mile" technology connecting users, WiMax is developed to replace broadband wired networks such as DSL and support mobile broadband wireless access, it uses OFDM transmission technology for NLOS connections, providing a data rate of up to 75 Mbit/s. The IEEE 802.16-2004 physical layer is divided into two modes:

Chapter 4 Reuse Frequency Division Multiplexing Time division multiplexing Synchronous time division multiplexing Statistics time division multiplexing Asymmetric Digital user line Chapter 4 Reuse Efficient use of high-speed data communication links-Reuse The capacity of a single data link can be shared by multiple information sources. Reasons why reuse is widely used The higher the data rate, the higher the cost-effectiveness of transmission facilities. Most data communicat